That looks like the back-up light switch for a 5-speed, which sits low down on the trans. On a 5-speed, the T/C sensor switches are the same mechanically, but have a short lead to a plug, instead of having the plug built-in. Go rearward to the T/C and higher up--one on each side.

The above is true for a 5-speed, and I would think applies to all j-shift T/C's, but I don't know what the switches on a multi-mode look like.

You need more than the push-button input for the 4wd ECU to call the front diff by switching the VSV's. It needs to know if the T/C actuator has engaged the front drive shaft to the T/C. That's what those T/C switches do.

 

Turned out to be a sticky rear actuator. Just took the thing apart and worked the electric motor back and forth with a 12 volt supply. Then kept working the motor as I put back together and works perfect now. That's not bad for a 1998 4runner limited automatic with 319,000. This and a leaky fuel injector are the only repairs ever done. And I'm getting 19-20 mpg.

 

I am having the same issue. 2000 3.4L with manual transmission, manual 4wd shift. Won't engage to 4wd under any circumstances- low speeds, high speeds, putting in reverse, etc. But if I move the 4WD shifter to N, that works fine. But will only go back to 2WD, regardless of where the shifter is slotted. No lights at all indicated 4WD is on.

And although I am an idiot by trade, I did check fuse and that's not it.

 

What do you mean it works find with the 4wd shifter in N?

 

I mean it goes into Neutral when shifter is in Neutral. Put the shifter anywhere else and it goes to 2wd. No flashing lights, steady light, etc.

 

Do you know where the VSV solenoids are located. Under the fuse box behind the power steering pump.

 

I spoke with my usual mechanic and he mentioned the same thing. I am taking it in Friday- will let you know what the diagnosis is then.

 

It was the harness for the front actuator