I've read through a number of the threads, but haven't found a resolution to my issue.

1999 4Runner limited multi-mode 4wd with manual j-shifter and 4wd button on transfer case lever.

Press 4wd button and nothing happens.
Manually shift to 4wd and nothing happen. No dash indicator lights, no click behind glove box.
Shift to 4low, low range engages, but no 4wd nor dash indicator lights.

Started at top. Vacuum line to VSVs provides vacuum at 20 mg through check valve to VSVs.
VSVs do not have vacuum. No switching with the 4wd lever.
VSVs do not have power to either solenoid. No switching with the 4wd lever.

All VSV lines and vacuum tank hold vacuum at 25 mg.
Rear protected line to front diff actuator engages actuator when manually connected to the vacuum line from the engine.
Front protected line to front diff actuator disengages actuator when manually connected to the vacuum line.

Front diff. actuator work correctly when vacuum is applied.
Front diff. actuator switch was removed and cleaned. Functions properly when checked with an ohm meter.

Transfer case actuator engages and disengages with power jumped directly to the switch.
Both switches on the transfer case actuator were removed and cleaned. Both function properly when checked with ohm meter.

I cannot get to the two switches on the driver's side of the transfer case near the top. I even cut a 27mm wrench in half and can't get the box end or open end on those switches.

Also cannot get to the one switch on the passenger side of the transfer case near the top.

4wd ECU has power to the black wire with white stripe. Also has a ground that checks normal on the white wire with black stripe. I don't have the ability to back probe the connections, so can't really trouble shoot more than that.

All fuses have been replaced and check good with a test light, ohm meter, and visually. All relays in engine compartment have been swapped around to check function and work normal in different positions.

There's supposedly a relay somewhere behind the passenger side kick panel. I can't find it. Does anyone have a picture of this relay? I think this is my problem as everything works separately, but nothing has power as a system. In the repair manual it looks like power goes through this relay right off the bat.

I also have a random white connector behind the driver's side kick panel that has no where to connect. Any idea what this is for?


I'm stuck with no 4wd. Any ideas?

 

I had a similar issue with a 2000 5 speed, details are here: https://www.yotatech.com/forums/f2/4...r-5spd-271572/

The fix was replacing the sensors on top of the transfer case (the ones you could not reach with the 27mm wrench). I know my 4WD system is different than yours, but when the J-Shifter is moved to 4WD, it activates the switches on top of the transfer case, which then activates the VSS and engages the front diff actuator.

From your description, it sounds like everything is working (front diff actuator) when you manually apply suction, you just aren't getting the VSS to kick in when you select 4WD?

-batsoff

 

Correct, just not getting power anywhere. VSS's or otherwise. How did you get those top sensors out?

I've thought about dropping the cross member and dropping the transfer case an inch or so, but not sure what would need to be disconnected to do all that.

 

I do have one brand new transfer case switch that I bought from Toyota for in case of, and I do have a good working 4wd ECM for a 99 4Runner for sale. If you need something let me know.

Doug

 

I wasn't able to get to those sensors either, I actually took it to the shop for some help with that.

I think you are on the right track, the only way I could see to get at those switches would be to drop the transfer case a little bit.

-batsoff

 

Still not working. Trying to get the upper sensors out, but they're near impossible with the tools that I have.