The factory Toyota electric locker has been available factory installed since the introduction of the Tacoma in mid 1995. It was first available in the “SX” package model, which was available only on regular cab six cylinder trucks. The “SX” was the precursor of the “TRD Off Road” package. With the introduction of the TRD package in 1998, the locking differential was included as part of this package. The TRD package was available in both four and six cylinder extended cab Tacomas. It was also included in six cylinder Prerunner and six cylinder TRD double cab trucks. It was available in the LX package which became the Limited model in 1998. This locker is related to the locker available in the 1991-1997 model Land Cruiser. The Land Cruiser locker packaged included front and rear lockers. This option (both front and rear lockers) disappeared when the Land Cruiser lost its solid front axle and went IFS in 1998.
The locking differential was and is actually a separately available Toyota production option, option code DL. From 1998(?) to 2002, one could order ANY 4 wheel drive Tacoma with the locking differential options. The process required your local deal to follow and option additional override process that would essentially override an ordered vehicle and add the requested option (option code DL) to the vehicle as it was in the input queue awaiting production. With the 2003 model year, this was eliminated as an available option for four cylinder trucks. To the best of my knowledge, the DL option could still be added to a 2003 or 2004 six cylinder four wheel drive or Prerunner model.
The Toyota electric locker is a stout 4-pinion unit. It is a “state machine”. Electricity is only use to switch states, not to maintain it. This is very good for off road or emergency use. If the differential wiring or controls were to be damaged or disabled off road, the locker would remain locked. This is the primary advantage of this locker in my opinion. Another worthwhile feature is that it is computer controlled. The factory computer prevents it from being engaged at any speed over five miles per hour. This saves the unit from grinding , and it probably would if someone attempted to engage it while spinning the wheels at 50 or 60 mph.
After trading in my 2002 four cylinder TRD truck for a 2004 extended cab four cylinder, I began searching the net and cross-referencing components to determine exactly what needed to change. I had the advantage of having access to my “old” truck, which was a 2001 4x4 Regular Cab Tacoma that I had ordered with the locker option. I also had access to my 2002 extended cab TRD truck that I traded in. Unfortunately, neither of these had 4 wheel ABS which the 2004 trucks have. Some of the preliminary question you need to ask:
1 – What is the axle ratio of your truck? I’d advise you to TRIPLE check this after getting the axle code off of the door. All 3 of my trucks read B07, which is a 4.30 ratio rear. The Tacoma literature lists 4 cylinder 5-speed trucks as a 3.9 ratio. NONE of the Toyota literature back to 1995 shows a 4.30 ratio. One Internet site also incorrectly lists B07 as 3.91. My advice is to check the existing axle manually before ordering the parts. Do this the old fashioned way – by jacking up the rear of the vehicle. Turn the drive shaft and count how many times the drive shaft has to turn for one of the rear wheels (one wheel must be on the ground since it’s an open rear…). Do it now or you might be stuck with a $1000 carrier that is geared wrong!
2 – Does your truck have ABS? The ABS harness is different than the non-ABS harness and this part of both of the harnesses must be changed when the locker is added. ABS rear housings are different than non-ABS housings in the earliest years.
3 – What parts are you going to need to replace when you do the swap? My truck was new so I only replaced the components that could not be reused when the swap was done. For an older truck, you might want to replace any other part that looks or feels beat.
4 – Check out other related sites on the net. Two that I can recommend are listed below:
The first is a “low budget” swap of the locking carrier into an open housing. It is very well written and an excellent starting point: http://www.4x4wire.com/toyota/tech/electric_locker
The second is a discussion and a patch that will allow you to lock the differential in two wheel drive (or 4 high):
5 – Obtain or read the Toyota factory manuals. I bought a full set since I intend to keep my 2004 Tacoma (Thanks Toyota, the 2005 Tacoma sux. The Tacoma is now Tundra sized – if I wanted a Tundra, I’d have bought one). The manuals are expensive but worth it. There are three of them. I have 25 years of mechanical experience so I didn’t need a detailed guide. I DID need things from all three manuals such as wiring diagrams and the factory torque specs. There are two service manuals and one electrical manual. For the 2004 Tacoma, the services manuals are RM1090U1 and RM1090Ud and the electrical manual is EWD565U. These are available from Toyota’s Materials Distribution Center (MDC) in Long Beach, California. Their phone number is 1-800-622-2033; the MCD web site did NOT indicate that these could be ordered electronically.
Any successful project starts with the right parts. For one-stop parts shopping I personally recommend the folks at partznet.com. Partznet.com is the Internet parts department of Conicelli Toyota in Conshohocken Pennsylvania. These guys four wheel and race cars. Sean, Tom, Frank and their boss Steve really know parts and wiring and it shows.
I developed a spreadsheet matrix (not included here) worksheet which listed the VIN’s from four trucks – my 2002 TRD 4 cylinder without ABS, a 2002 TRD 6 cylinder with ABS, my 2004 4 cylinder open rear truck x-cab with ABS and a 2004 TRD 6 cylinder 5 speed truck with ABS. In this manner I could see what parts were the same and what were different. Double-checking and cross-referencing is crucial in a swap such as this where there is no room for error. Screw up and you might be stuck with a thousand dollar part.
Armed with my spreadsheet, Sean at Conicelli looked up the parts and provided insight as to what the differences were. We determined that:
1. The carriers are the same from 1995 ½ to current (2004). The
only difference is the ratio.
2. Axle housings are NOT the same for all years. MY truck required a 2002 – 2004 six cylinder ABS equipped extended cab locking differential housing.
3. Most (but not ALL) of the wiring is in place for the locker. For obvious economic reasons, there are gaps.
4. The bracketry is the same in 2004 for both locker and open rears.
5. The axles are the same from both open and locker rears/housings.
These are the required parts with the Toyota. The prices shown are Toyota’s MSRP for the parts as of 12/1/04.
The part number line includes the Toyota Description of the part according to the parts computer system.
Vehicle – 2004 Tacoma Xcab 4x4 2.7L 5-speed
4.30 ratio with 4 wheel ABS (43:10 ring/pinion count)
Axle code B07A
Toyta Part #
|Rear Axle Housing – 2004 Tacoma Xcab 4x4 V6 5-speed, ABS, locking diff.||
|Housing Assy, RR||
|Rear Differential Assy – complete
4.3 locker – 95 ½ - current 4.3 ratio locking diff. (43:10 ring/pinion count)
|Carrier Assy Differential||
|Gasket– Carrier to Housing, locking differential||
|Rear Axle Filler/Drain plug gasket (2 required)||
|Gasket, Drain Plug||
|Rear Axle housing “wheel” seals (2 required)||
|Seal, Type S Oil||
|Mounting Studs - Locking Differential to Housing|
Long (2 required)
Medium (2 required)
Regular (9 required)
|Locking Differential Computer||
|Computer, 4 Wheel Drive||
|Dash Switch – Locking Differential||
|Differential Wiring Harness – Locking diff to frame harness, with ABS||
|Frame Wiring Harness – Complete - From BN7 front harness connector to rear diff harness||
|Electrical Connector – Frame harness to locking
Connector B01 female (frame wire and differential #2 wire (rear side member LH))
|Contacts/pigtails for Connector B01 (all-weather), 7 required||
1. Eleven (11) metric grade 8.8 flat washers and hex nuts for the above studs.
2. 3.2 quarts 75W90 Synthetic gear lube (note this is a change from open rear).
3. Wire – 20 feet of 18 gauge automotive wire (5 colors – 100 ft. total) and 20 feet of 14 gauge white automotive wire.
4. Six feet of ½ inch diameter plastic wire sheathing.
5. 1 quart of DOT3 or DOT4 brake fluid.
6. 1 roll of electrical tape (Premium quality 3M 33 or 88 preferred).
7. Miscellaneous wires, solder, etc.
The Process: I will list the steps required to perform the swap AS I PERFORMED THEM and TO THE BEST OF MY RECOLLECTION. Follow standard safety precautions. If you’re too stupid to work on cars safely, do something else for fun or money.
Removal of Rear from Truck:
· Jack up vehicle, remove both back wheels. Truck should be on jack stands at factory specified locations.
· Unbolt drive shaft from rear companion flange. Tie up drive shaft to truck.
· Remove clips from parking brake cables to backing plate hangers. Pull pins out and be careful to keep clips and wave washers.
· Remove parking brake support hangers from housing. Tie hanging cables to truck and put brackets/screws back on housing.
· Unplug the rear axle ABS wire from the frame harness connector. Remove the axle ABS wire connector from the body /frame bracket.
· Remove brake equalizer bracket from housing. Put screws back in housing and tie equalizer rod up to body/frame. DON’T let it hang loose!
· Unclip brake hose from frame mount.
· Using metric line wrench, remove brake hose from rear frame brake line. Plug up frame line and rubber line to keep dirt out.
· Unbolt shocks from shock mount. Put 2 bushings, cap washer, and nut back on each spring from seat shock bolt for safekeeping.
· Put floor jack under center of axle
· Remove U-bolts from both sides.
· Lower jack and axle; remove axle assembly from truck.
· Unscrew both sides of the brake line from the wheel cylinders
· Unplug the ABS sensors from the axle wire. Unbolt and remove them from axle housing.
· Remove the 4 backing plate nuts and slide the entire axle assembly out of the old housing. Do both sides like this.
· Clean the old axle assemblies with solvent to prevent gear lube compatibility problems.
· Remove the filler and drain plugs from the old axle housings.
· Clean the differential gasket mating surfaces of the new housing to remove paint, etc.
· Clean the inside ends of the axle tubes of the new housing to remove paint, etc.
· Clean the inside and mounting pads for the ABS sensors of the new housing to remove paint, etc.
· Clean the gasket-mating surface (mounting surface) of the new carrier with solvent.
· Screw studs into the new housing. The factory thread locker is on the side that goes IN THE HOUSING. There are 2 long studs that will go where the locker motor is. There are 2 slightly longer studs that go outside of these (you’ll see the raised pads on the carrier itself). And the rest of the studs are the “normal” size.
· Place the carrier over the studs to ensure that none of the stud shoulder is showing. If it is, either the stud isn’t in far enough or you have the wrong stud in the wrong place. Or maybe you don’t need both of the slightly longer studs; the regular ones might be long enough.
· When you’re happy with the height of the studs, take the carrier back off.
· Clean the housing mounting pad again and put the differential gasket on the housing.
· Place the carrier back on the housing and put the flat washers on over the studs.
· Put Lock-Tite on the threads, put on the nuts and torque to factory specs. Use a cross pattern to recheck the torque.
· Press in the axel seals into the axle tube. HINT – if you don’t have a seal-installing tool, you can make due with a piece of 2-inch PVC DVW pipe SPLICE. It is the same diameter as the seal. Use a 2x4 to tap on the PVC pipe splice and carefully drive the seal home.
· Lube the rubber inner axle seals with grease.
· Put grease on the axle O-rings and on the housing mating surfaces. Slide the O rings onto the rear housing and against the backing plate face.
· Carefully slide the axles into the new housing taking care not to damage the inner axle seal. Make sure the O-ring is still where it should be on the outer housing against the machined face before driving the axle retainer against the housing. The emergency brake hangers go to the REAR of the housing.
· Replace the 4 axle retainer nuts on the studs in the backing plate and carefully tighten them watching to ensure that the axle retainer is flush with the backing plate. It MUST be flush on all 4 sides.
· Torque the axle/backing plate retaining nuts to factory specs.
· Place new gasket on the drain plug and replace in new housing. Torque to factory specs.
· Remove the screw-in breather from the old housing and clean. Re-install to new housing.
· Fill housing with 3.2 quarts of 75W90 synthetic gear lube (synthetic as per factory specs).
· Place new gasket on filler pug and torque to factory specs on new housing.
· Insert the ABS sensors into the housing and toque mounting bolts to factory specs.
· Remove brake line and bracket from old housing and replace/re-install on new housing.
· Tighten brake lines where they screw into wheel cylinders.
· Connect both plugs from the differential wiring harness to the differential.
· Connect the motor breather tube to the locker motor fitting.
· Connect the ABS wiring harness plugs to the ABS sensors.
· Fasten the wiring harness snap connectors, brackets, etc to the new housing.
· Remove remaining brackets/bolts from old housing and replace/re-install on new housing.
>Re-install Rear in Truck:
· Place center of completed axle on floor jack and carefully guide under truck.
· When axle is centered under springs, raise carefully ensuring that the bolt in the spring fits into the hole in the spring mounting pad on the axle housing.
· Place mounting pads under axle and install U bolts, washers and nuts. Torque to factory specs.
· Remove shock nuts, bushings and cup washers. Place bushing, shock, cup washer and nut back on shock bolt.
· Re-torque shock nuts to factory specs.
· Re-install all emergency brake brackets. Torque to factory specs.
· Re-install equalizer rod and bracket. Torque to factory specs.
· Fit brake hose to mounting bracket. Replace clip. Screw brake line nut into brake hose.
· Using metric line wrench, tighten brake line to rear axle brake hose.
· Re-install parking brake cables, wave washers and pins and retaining clips.
· Re-install drive shaft and torque nuts to factory specs.
· Install ABS/Diff lock wiring harness bracket to fuel tank mount.
· Slide ABS wiring harness plug onto the frame bracket. DON’T put the diff lock plug on the bracket yet.
· Re-install (plug in) the wiring from the frame harness to the ABS wiring plug.
· Insert diff lock breather line grommet into hole in frame.
· Clean and re-install brake drums.
· Bleed the brakes.
***HINT*** BEFORE bleeding brakes, re-install the brake drums and using
box wrenches as spacers between the brake drum and the lug nuts, install
3 or 4 lug nuts on each side to hold the brake drums in place. Snug up
the lug nuts against the box wrenches just enough to keep the brake drum
squarely on the axle. Makes the job much easier!
· Put on the wheels/tires and put truck back on ground.
For our purposes, we can break this down into 3 major components:
1. Cowl wiring (cab wiring). This consists of all inside-the-cab wires that are necessary for the locker controls. These are present in ALL four-wheel drive Tacomas. The plug for the locker switch is just behind the dummy plug that is in the dash where the switch would go. The plug for the computer is in the kick panel taped to the wiring harness. All of the necessary “behind the scenes” wiring is present here.
2. Frame wiring. This consists of the wire that runs from under the drivers’ seat (26-pin connector BN7) to the rear frame (7-pin locker connector BO1 and 4-pin ABS connector B02). This piece of wiring is NOT present in the frame harness wire on trucks without the factory locker.
3. Differential wire. This consists of the wiring harness that connects the frame wire to the rear axle housing, ABS sensors and locking differential motor. This harness is NOT present on trucks without the factory locker.
The differential wire harness is a necessary part of the swap. Its part number is in the list above. If you have a non-ABS truck you will have to find out and get the part numbers for that harness and it should be a bit cheaper.
The situation with the frame wiring is this: All of the 26 front harness wires are present going INTO the harness connector BN7 under the front seat. Unfortunately, only 21 wires come out of the BN7 connector into the frame wiring harness. 5 of the necessary rear locking differential wires are not present in the frame wiring harness of non-locker trucks.
The frame harness (from connector B07 to the rear of the truck) contains all of the OTHER necessary rear wiring. This includes the brake and turn signals as well as ABS wiring and fuel pump and fuel tank wiring.
You will have two choices with the frame wiring. You can but the rear frame harness Toyota part number 82164-04641 and replace the non-locker harness with this one. This is truly “plug and play”. The only drawback is the expense ($297 list price) and the time required to disconnect all of the components from the “old” harness and install the “new” harness and hook up all of the connectors and components. I suspect that it would take anywhere from two to eight hours to remove the old rear wiring harness and re-install the new one and connect up all of the components. This is truly the preferred method to take with this swap. It’s the safest and simplest if you’re not good at wiring.
In my case, I simply did not have time to wait for the harness to be ordered in or to remove/replace the entire frame harness. I chose to make an intermediate harness. This “intermediate” harness consists of six-conductor patch harness that uses factory splice connector pins to tap into the front connector B07. It then follows the existing frame harness to the differential wiring bracket on the frame by the fuel tank. There it terminates in a factory B01 female connector with female pins.
If you do not have the expertise to do this I recommend that you buy the harness. If you have the ability to ACCURATELY trace wires and can follow my directions real closely, you should be able to make the harness that I made. The most difficult part here is making everything the right length to fit properly. If something is too long, you runt risk of snagging it off-road (OR on road) and ripping out thousands of dollars of wiring. If it is too short, it might not fit or it will not allow for enough “normal” flexing and you will tear up wire or connectors and have equally big headaches.
With that said, here is what I did to make the missing wiring harness. It took me about 2 hours total to do this. It is REAL trick to do but it worked fine for me.
· Take 6 feet of ½ inch plastic wire tube and loosely fasten it to the existing wiring harness tube. This is just for length fitting. You want the end of the tube just at the top of the rear frame rail above the fuel tank. It should end at the same place that the ABS wires come out of the existing plastic tube on the frame. In the front, the tube should end on the inside of the frame at the spot where the factory wiring harness crosses over the top of the frame in the white plastic bracket. Your goal in this exercise is to make the wiring tube long enough to protect the wires under the frame because the wiring bundle will be taped together where it exits either end. Where the wires come out of the tube in the back, they will be taped into a bundle and will go from the frame to the locking differential connector. Where the wires come out of the tube in the front, the wire will be taped together to cross over the frame. They will then be fed into the “nibble” style grommet that feeds the frame wire bundle into the cab floor.
· Once you’re happy with the length of the wire tube, you will need to determine how much wire must come out of the rear of the tube and hang over to the differential wire connector B01. There should be a short loop of wires that allows flexing (like the way the brake hoses are in the front of the vehicle) but not so much wire that the looped wire rubs on ANYTHING. This is necessary because the wire tube is fastened to the frame, and the connector and its hanger are fastened to the body. Like I said, getting the length right of things is the trickiest part of making this harness.
· Now you need to start actually making the harness. I have nicely listed for you the wiring colors. Due to copyright limitations, I cannot reproduce any of the Toyota factory schematics or diagrams. If you aren’t sure what I’m talking about, buy the Toyota factory electrical manual.
· Start by stripping the ends of each of the seven 82998-12440 wiring splice pigtails. Solder one to each of the colored 18 gauge wires. Solder TWO ends together on one 14 gauge white wire. This is the ground wire. Carefully tape each of the individual soldered connections. Do not tape all of the wires together as a bundle yet!!
· Now comes another tricky part. You will need to match up your wire color with the one in the factory B01 connector. I didn’t have any quick source of multi-color-coded wire so I made due with standard (red/black/blue/green/yellow/white) wire colors.
Differential wire #1 – light green/yellow -- to RED wire on 90980-10931
female connector pigtail
Differential wire #2 – light green/black -- to BLACK wire on 90980-10931 female connector pigtail
Differential wire #3 – solid light green -- to GREEN wire on 90980-10931 female connector pigtail
Differential wire #4 – light blue/yellow -- to YELLOW wire on 90980-10931 female connector pigtail
Differential wire #5 – light green/red -- to BLUE wire on 90980-10931 female connector pigtail
Differential wire #6 – white/black -- to WHITE wire on 90980-10931 female connector pigtail
Differential wire #7 – white/black -- to WHITE wire on 90980-10931 female connector pigtail
Hint – use color combinations that I have chosen. You will see when you do the front wires why I used “light green/red to BLUE”, etc.
Please note that the way to make things MORE confusing, the tiny numbers stamped into the connectors do not always correspond with the factory manual. I have listed the wire numbers above as they are specified in the Toyota electrical manual.
· Now that you know what color goes to what, you will need to push the metal end of the connector pigtail into the BACK of the 90980-10931 wiring plug until it clicks into place. You need to be EXTRA careful here. My suggestion is to pull the differential wire male connector as close to you as you can without mating it and one-by-one insert the pigtails into the back of the female connector. If you connect the two plastic connectors before pushing the pigtail plugs, you will have to push extra hard and be extra careful putting the leads into the plastic connector. Once the pigtails are snapped into the connector, they can’t come out. For these “all weather” connectors, the rubber seal should be flush with the back of the connector when the pin is pushed all the way into the connector.
· Once you have all 7 pigtails inserted into the 90980-10931 B01 connector, DOUBLE CHECK THE COLORS AGAIN. Make sure that, for instance, the YELLOW wire is going in yellow and coming out the on the other side of the connector as light blue and yellow.
· Once you have connected the pigtails to the connector you should have a bundle of 7 wires with pigtails and the B01 connector on the end. Carefully determine how much wire has to stick out of the tube that you have up along the existing frame harness tube. Once you figure this out you should tape all of the wires together starting at the B01 connector and going back to where the wires enter the plastic tube. Here, you will just start the wires in the tube and wrap the tape around just the end to hold the wires in the tube.
· Now you should have the plastic connector (with the 7 pigtails connected to it), a few inches of taped wire bundle, and then the 6-foot or so of wire tube with the individual wires dangling out of them. Unfasten the plastic tube from the factory one and pull the tube back out of the frame. Carefully feed the bundle of 6 wires through the rest of the tube and run a ring of tape around the plastic every 6 inches or so. When the wires are fed all of the way through to the end, you should have what looks like the plastic wire tube with a connector at one end and a bundle of wires (6 different colors) at the other end.
· Now comes another tricky part. You will need to go to the FRONT of the truck, just under the driver’s door and begin to feed your homemade wiring harness back. You want to make your wire tube sit right next to (or on top of) the existing tube. As you carefully (and with some difficulty) feed it backwards you will keep an eye on where the wire is. When the wire tube goes far enough back to allow the 90980-10931 plastic connector to mate with the male connector that comes from the differential wire, you know you are there. If you did it right the plastic tube should end in the front somewhere around where the existing wire bundle goes from the inside of the frame to the outside.
· Locate the grommet that allows the existing wire bundle to enter the cab. It looks like a cross between a baby bottle nipple and a rubber. What the factory does is push the taped bundle of wires into the grommet and then run a ring of tape around the outside to seal it. You need to peel this ring of tape off so that you can feed your 7 wires from the bottom, up thought the existing grommet and onto the cab floor. Again, this is tricky. You don’t want to tear the rubber grommet since this seals out water from getting into the truck when you go through those deep puddles and fords. And you don’t need to un-tape the existing “factory” bundle of wires.
· Once you’ve un-taped the end of the rubber grommet, you’ll need to get some access in the cab. Remove the door trim plate and kick panel. Unbolt the driver’s seat and remove it or tilt the whole thing back and out of the way. Peel up the carpet under the driver’s seat and you will see the wiring harness bundle and the 26-pin connector lovingly known as “BN7” to Toyota. Getting it out of the plastic holder is tricky. Once you get it free, pull the connector, wires, and everything to the outside where you can see it. If you push down on the ridged black piece of the connector, it will allow you to pull the connector apart. But before doing this, notice that not all of the black “holes” in the connector are filled in. This will be your job – to take those seven loose wires coming from the back and stuff them into the right parts of this connector.
· Next tricky item – For each of the 6 colors of wire, you need to feed the wire from where it comes out of the plastic tube on the frame up through the body by unseating the outside of the grommet and pulling the grommet completely downward and out of the cab floor. You can then sit under the truck and feed the wire through the grommet and then through he hole in the floor and into the cab.
· When all is said and done, you should have a messy bundle of loose wires on the cab floor but a nice compact bundle under the truck. I’d suggest that you wrap tape around your 6 loose wires and the existing bundle. What you will have down below is two bundles of wires (coming out of your tube and another larger taped bundle coming out of the other “factory” tube) joining together at the nipple grommet that enters the cab.
· When you’re satisfied that the lengths are right down below, you must tape all of the wires underneath of the cab end into a bundle. You must wire tie your plastic tube to the exiting frame. You should do this every foot or so for he full length of the bundle. Preferable your wire tie would be around both bundles in the place where the factory bundle is fastened to the plastic frame connectors.
· Once this is done, you might re-insert the grommet back into the cab floor. If it’s done right, you should have a nicely hidden second wire tube right next to the factory one. On one end (the back end) will be a taped loop of wire and on its end will be the connector to the differential wire. In the cab, you will have a pile of 6 different color wires in a pile on the cab floor under the seat. You should cut off the excessive footage of the loose wire leaving enough to connect the 6 wires to 6 pigtails that will be coming out of that huge 26-pin connector.
· Now we have a different color match and different numbering scheme. For the under seat connector BN7, you will need to connect the colors as shown:
BN7 wire #10 – light green -- to GREEN wire
BN7 wire #11 – violet -- to BLUE wire
BN7 wire #12 – light blue/yellow -- to YELLOW wire
BN7 wire #14 – pink -- to RED wire
BN7 wire #15 – light green/black -- to BLACK wire
BN7 wire #21 – white/black -- to WHITE wire
· You should strip off the ends of the 82998-12340 repair splices and insert them into the BLACK BN7 connector in each of the remaining spots. Depending on whether your truck has ABS or not, there should be either 4 or 5 empty spaces in the back to fit your connectors to.
· After inserting the connectors, follow the pin to the FRONT connector and determine what wire colors there. Based upon that, solder the appropriate colored wire to the splice based upon the above chart.
IMPORTANT NOTE – The BACK of the BN7 connector pins # 10, 11, 14, and 15 are blank with no wires coming out of them. On ABS equipped vehicles, pin #12 has a yellow/light green jumper wire coming out of it. You will need to cut this wire on the BACK side (yellow/light green side) and then splice your YELLOW wire to the yellow/light green wire stub coming out of the BACK of the BN7 connector. Tape off the remaining piece of the yellow/light green wire. What you should see here is your YELLOW wire spliced to a short length of yellow/light green wire that goes into the BN7 connector and comes out the front side as a light blue/yellow wire. If your vehicle does not have ABS, you should simply insert a splice to the #12 hold and solder on the yellow wire.
IMPORTANT NOTE #2 – Connector pin #21 has a white/black wire on both sides of the connector. You will need to strip off a ½ inch section on the BACK side and splice in the WHITE wire.
You should now have a completely wired locking differential. You need to TRIPLE CHECK the wiring – look at the above charts for BOTH the front and rear connectors. Follow them to make sure that the factory colors match up to YOUR colors according to the chart. In summary they should be:
Light Green/Yellow wire #1 at B01 – to your RED wire – to
BN7 wire #14 Pink.
Light Green/Black wire #2 at B01 – to your BLACK wire – to BN7 wire #15 Light Green/Black.
Light Green wire #3 at B01 – to your GREEN wire – to BN7 wire #10 Light Green.
Light Blue/Yellow wire #4 at B01 – to your YELLOW wire – to BN7 wire #12 Light Blue Yellow.
Light Green/Red wire #5 at B01 – to your BLUE wire – to BN7 wire #11 Violet.
White/Black wire #6 at B01 – to your WHITE wire – to BN7 wire #21 White/Black.
White/Black wire #7 at B01 – to your WHITE wire – to BN7 wire #21 White/Black.
· If all of your wiring is setup correctly so far, you are ready to finish. Carefully pry out the blank cover in the dash where the diff lock switch goes. You should be able to see the 5-pin connector just sitting behind the dash in amongst the clump of wires. Carefully pull it out and push it into the diff lock switch. Stuff the diff lock switch into the dash.
· Behind the driver’s seat kick panel, you will see the bundle of wires that goes into the fender. Look close and you’ll see a white 10-pin connector hanging around the bundle of wires. This should mate up to the locking diff computer. You’ll need to fasten the computer to something. In my truck, the bracket for the computer wasn’t on the floor so I couldn’t use the factory computer bracket. I got some permanent mount Velcro and used it to mount the computer to the kick panel.
· Now is the time to cut and splice the gray wire to a ground if you want to bypass the factory 4WD limitations. See the links in the notes at the top of this article to see how it’s done.
· QUADRUPLE CHECK EVERYTHING, including wiring, leaks, and everything else. If it looks good, bolt in the seat, replace the kick panel and put the computer trim plate back on. If you did your homework right, you should be able to push the locker button and the light will flash until the differential locks. The differential should lock (speed should be under 5mph) with a nice click. On ABS equipped trucks a relay will also click and the ABS light will go on indicating that the ABS is disabled. If you push the button off (at any speed) the RR DIFF LOCK and ABS lights should go out and the locker should click and unlock.
THANKS AGAIN to al that made this project come together as perfect as it did!
Coming next, a high approach angle conversion for Western ‘UniMount’ snowplow frame mount on 1995 ½ - 2004 Tacoma. From plow truck to rock truck in 30 seconds!
Entire document copyright Robbie M. Mondichak 2004. Reproduction and distribution
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Always wear your seatbelt, drive safely, and keep your wheels down.