SAS 4WD indication

2003 4WD 5vzfe manual truck.

I’m in the process of gathering all info I can for my SAS. I’ve looked thoroughly through this forum and others and can’t seem to find a sas with a push button 2-4hi transfer case. I know they’re out there.

I’ve verified the transfer case will shift to 4WD with ADD connector removed from actuator(driveshaft spins). 4WD light on dash does not illuminate though.

I jump pins 3-4 to ground out “add detection switch” and 4WD light stays illuminated, even when I remove jumper, until I take transfer case out of 4 wheel.

Can someone with first hand knowledge, who has the push button transfer case in their first gen, let me know if this the standard way of fooling the 4WD ecu in this truck?

Attached wire print for context. Wish I could see the logic inside the ecu because the diagram shows limited details on the logic behind the 4WD light.

 

99.9% of SA Tacoma owners will either swap the H/L case for a J-pattern or wouldn’t care if the 4wd light work after a SA swap.

I had an ADD but swap to J-pattern and SA. I tried to study the schematic after I swap over to the J-pattern case because I wanted a Rad triple stick and the light to work. I gave up and ended up keeping both actuator, keeping the tcase actuator in the same spot as the H/L tcase location, modified the forks and made a mounting bracket for the front ADD. Added a reverse light switch to the 2/4wd shift rail on the J-pattern tcase to engage the push button when I shift to 4wd, which engage both actuator and turn on the 4wd light.

Yea, sounds stupid, others will laugh and say that I have too much time but I wanted the light to work and try to keep everything as original as possible.

Picture 1: J-pattern case with H/L actuator
Picture 2: modified front ADD to frame
Picture 3: reverse switch at 2/4wd shift rail
Picture 4: shifter
Picture 5: 4wd functioning as original

 

Haha it works. I can’t stand when the little things don’t act factory, so I’ll find a solution. I think jumping those contacts will be satisfactory in the long run. If not, I can run this t case and just keep the ADD, mount elsewhere, like you did. Truck won’t know anything’s changed.

 

Iirc, there’s a 4wd detection switch on the top of the transfer case actuator. I would jump the g/b wire from the add actuator to that switch and see if it illuminates when shifted (it should, it’s just looking for that same ground signal the 4wd switch is giving).

When I swapped to gear drive cases, I connected the wire directly from the cluster to the 4wd switch. I don’t see why this wouldn’t work either.

 

That’s a really good idea. Of course the print doesn’t show which is for 4w/2w input to the ecu. I’ll see which has a ground when later this week. I’ll go this route if my initial plan doesn’t hold up.

splice at yr or p (whichever is for 4w) and it’ll ground out that add detection switch and 4w detection both at once. Thank you

 

Oh correction, I’ll splice into r-l. That would work.

 

R-l will work yep. I’d test to verify with jumper wires and back probing, but don’t see why this wouldn’t simplify and solve the problem