2001 tacoma double cab. 4x4 not working

What year is the Tacoma? And it's TRD 4X4, right?

 

Not asking redundant stuff on purpose, bear with me. Gonna find an FSM, too hard to guess through this stuff. We need real information

 

the wiring is on top of the glove box. There is a black panel on top.
The 4x4 ecu is below the radio area.

 

2001 TRD Auto. Thanks for the help. I really appreciate it. Got a wiz bang electrical guy coming over tomorrow, so Hopefully we can fully check this out.

 

here

PM'd you also

 

thanks for the info mechanicjon

 

Do not have wire continuity between 20 amp fuse and 4x4 ecu so no current going to ecu.. Now trying to track down where the wire break is. going to start by Looking at alarm system and if they made the clip on connection on the yellow black wire going from 4x4 fuse to 4x4 ECU? got my fingers crossed!

 

Does Not appear to be alarm hookup, but not 100% sure cause can't really see much with tangle of wires there and did not see a yellow black wire coming out of fuse box. Found yellow black wire junction plug above glove box that has continuity to ECU , but other side of junction is white wire, not yellow and black per schematic. Ran a fused hot wire from YB -Wht wire junction and got 12 volts to ECU, but still no action on TC or ADD actuator or dash light .

ADD unit checked out ok for resistance and motor ran. Did not operate ADD to see fork move cause could not figure out how to hook up according to FSM instructions using heater relay. I'd sure like to see ADD fork move off truck if anybody has any ideas on how to do wire it up for bench test. (FSM says don't put 12 volts direct to ADD and is extremely cryptic on the subject).

I ordered the FSM CD today and I'll check out the TC actuator when it comes. I appreciate the help so far but hate to keep bothering folks on this site to send me stuff.

 

https://cdn.discordapp.com/attachme...96542380146688/01_taco_connector_Location.pdf
https://cdn.discordapp.com/attachme...6576089505793/01_taco_compoenent_location.pdf

connector location and parts locations.. might help, check for corrosion around the kick panels if the wire runs through one of the plugs down there. not too uncommon in older Toyota to get corrosion there

 

https://cdn.discordapp.com/attachme...36797966417657856/01_taco_Relay_Locations.pdf

this shows the junction block up near the radio/passenger area that has the 3H and 3A connectors for the 4wd ecu. also what connector on the back of the interior fuse box (1J) to check.

looks like power for the 4wd fuse comes from connector 1l which comes from the engine harness. dont know what wire feeds it though.

 

Thanks for the info. I found a complete wiring shematic. I'm studying it now to figure out what wire goes where so I can trace the wire from fuse box to 4wd ecu since I have 12 volts to both sides of fuse. Its taking a while to get a handle on all the the info about wires , junctions, and references to connector location etc in schematic. The first few pages of the schematic are crucial to understanding the circuits since I'm not used to reading this stuff. Thanks again for the support. I'll report back on progress.

 

Looks like problem is bad 4WD ECU. Was able to by pass it and get TC actuator to work. Found manual shift transfer case with ADD for $125 that I plan to swap in to be done with the issue. I may go ahead and lock the ADD axel shaft together also to eliminate another fail spot. For my purposes, the 4x4 has to work every time. Thanks for the help from everyone.

 

Awesome work hermano. It sucks but at least you got to the bottom of it. Good to hear. And glad you kept us updated as this is bound to help folks in the future

 

Can't lock ADD in permanent without having manual hubs. But with a JShift and the two vacuum solinoid switches you dont need the 4x4 ecu.

 

Here is my plan. The all electric ADD was not working anyway- stuck in locked position (assume cause of 4x4 ECU) and the plastic breather nipple is broken off. Probably repairable but getting away from electric shift stuff. Thought I'd just put clamp on ADD fork shaft in axel locked position. Guess I could leave wire unplugged at ADD too. I'll have to Jump my wire from 4WD T case indicator switch to the indictor light near ECU so I know when its in 4x4. The indicator light is working and just needs to be grounded to turn on. Differential / front driveshaft will turn all the time but not too concerned about it. Truck does not have a lift. May go with lockouts later depending on how much the MPG is affected by turning front diff. I think this will get me on the road without dumping more cash into this thing for ADD and ECU??

For anyone who wants to stay with electric 4x4 and wants a good 2-4 select push button transfer case from 2001 tacoma and good actuator, I have one for sale. 117,000 miles. It has a High - low shift lever and button for 4 hi.

 

You'll regreat having the front driveline spinning all the time. It's super simple to wire up the 2 vac solenoids and eliminate the 4x4 ecu. The dash light will still work afterwards. The hardest part is removing the inst. cluster to tie into the wire.
Wait your not a vac shifted ADD. So you'll need a ADD vac actuator also. Still simple but it adds cost.

 

Usually behind the kick panel.
On the electric ADD actuator if it's good it can be wired up to a switch. (a momentary kind of switch ) I can work up a diagram and tell you were to get the switch if you'd like.

 

I don't think having everything in the front spinning will be an issue. I have an auto locker that spins my front driveshaft in 2wd all the time. No issues that I can think of from that.

 

Transfer case bolted up easy. Have 4x4 indicator light working and test drive was good. Front diff/ driveshaft spinning is less than ideal but truck is not lifted so not sure how much efficiency I'll lose. I would consider wiring up a switch for the ADD. Maybe a momentary switch like a "power window" type that would also be wired in to indicator light. That way, indicator light is off only when ADD and Tcase lever is in 4x2. A wiring schematic to do that would be helpful if you want to send one, thanks Mechanicjon. That would save me some head scratching as I'm almost out of hair as is! ADD unit may be salvageable or I could splurge for a new one. Either that or ad lockouts, but the ADD would be relatively easy to wire up.

 

Attached are a few photos of Tacoma DC frame repair if anyone is interested. Used a "Poor mans" lift and a stool on wheels which helped out. Also used the frame paint from NAPA which is a good product. Only left about 2 inches of original frame. IT was a ton of work but got the truck cheap and project kept me off the streets LOL!