Hello everyone- searched but didnt find much-
1995 4runner 4x4 - doing an oil change the other day and noticed a disconnected plug on the ADD unit. I found what I think is the correct plug, same color/correct pin and shape, coming from the same harness as the alternator wiring(driver side). Problem is the wires are not long enough to reach the ADD, so my thought is they must not b for the front diff... I have been on the trail many times and engaged 4x4 with success- without this plug attached. So my question- What is the plug for? Sensor or light?
Any wiring schemas or pics, or just general knowledge is greatly appreciated



Thanks

 

Well...are you sure the front tires were working? Is that cable zipped tied somewhere that is preventing it from reaching? It is possible someone went into the ADD and manual locked the shift collar....which would make sense why there's no plug going to it.

 

The ADD is controlled by vacuum.

All that switch does is light the 4WD light on the dash.

It's a simple position switch that is supposed to light when the ADD collar is in it's locked position.

The ADD can work, whether that light is hooked up, or not.

 

thanks, when I put in 4x4 I get the light on the dash, without this connected...
does anyone know if this cable comes from the driver side harness, with the alternator wiring?

 

Well, if your 4WD lights, the factory wiring has been modified.

The light should not light unless that ADD position switch is connected and closed, or unless the wires to that switch have been shorted; intentionally, or otherwise.

The ADD indicator wiring does indeed drop down from the alternator loom.

 

I'm fairly certain, that plug is what tells that vacuum to work for the Axle Differential Disconnect. The 4WD indication is driven of the shift forks in the t-case....

 

I've got a factory service manual wiring diagram that begs to differ with you.

There is indeed signal from the transfer case, and that signal acts on the ADD VSV's; but the 4WD light cannot light unless that ADD shift position switch closes to show that the front axle is actually engaged.

In fact, on machines of this vintage that were not built with ADD, a shorting plug is necessary on this ADD position lead in the wiring harness, to enable the 4WD light to illuminate when the transfer case is selected to 4WD.

There is substantial difference in wiring between manual and auto trannys, but both schemes require the ADD position (ADD detection switch) switch to be closed before the 4WD light might illuminate.

 

Boom! A schematic!!!!!!

You're welcome!

 

Ba Boommmm! thanks millball! Im coming thru AZ on my next trip, once this body swap is all buttoned up. Definitely owe u.
Although- being the novice schematic reader i am.. what does this plug actually do?
Looks like connector 'A'- 2pin, red and green wires.

3vze, auto transmission- just completed a 3.4 swap tho

Wires come down off driver side with the alternator harness. Wires do not reach the plug- tied to the body in 2 spots, even when i cut the ties cables still do not reach. Is this from the 3.4 swap?(although i dont see how if nothing moved) Ive engaged 4wd without this plug connected and get the light on the dash.

I also noticed the same plug, same wires (green,red) coming from the passenger side. connected to the engine harness. this plug does not reach either.

Now a 3.4, should I connect the passenger side plug? Or the driver side?
My plan is to extend the wires on the driver side and connect the plug, even if not needed.
Does anyone have a better idea/advice?

Thanks everyone!

 

This plug and switch does nothing but assure that the 4WD dash light does not light unless the ADD collar has actually shifted into the locked position.

Your ADD might still function perfectly, because the signal to the ADD shifting VSV's comes from elsewhere.

As I said previously, if your 4WD light is still lighting with this switch disconnected, someone has modified your wiring. It should not light with this switch disconnected.

 

Thanks so much!

 

You are welcome!!!!!!!!!