Kzn185 gen 3 4wd ECU ??

[maxigaz]

The 4wd ecu behind the passenger side kickpanel. Have you checked the ADD?
4wd won't kick in until it gets the signal from ADD(front diff) it is engaged.

[sauer]

Sorry but to me that is voodoo , I'm not the one working on this ... As six I'm struggling to get anyone to look at it ...
I just make the tea 😓

ADD ???? & how do you check it ? Where is it ?

Paul

[maxigaz]

ADD stands for automatic disconnecting differential. Normaly when you driving in two wheel drive you don't want the front wheels turn the axles and driveshaft because of fuel consaption. Old yotas have manual hubs. The hilux surf has an auto disconnect. Unfortunately not enough room on both side so only the right side(96+) has a disconnect mechanism. If you look under it is on right from the diff on the back. Pretty tight but you can try to disconnect the sensor switch.
http://www.toyodiy.com/parts/p_J_199...KPXT_4301.html

The mechanism operated by vacuum. Only the on/off sensor electrical.
The vacuum selenoids are on the left inner fender (one blue and one brown), Maybe it is not even electrical but the vacuum hoses disconnected...

One more thing. There are versions without ADD and electronicaly operated as well.Probably yours works with vacuum.

[sauer]

Cheers!!!!

We have the ECU in front left kick are clicking when push 4wd button , checked the electrical continuity of the wires from ECU to the brown & blue plugs on left wi g/ fender , that is good but when all connected ther is no 12v signal getting to either brown or blue solenid
So either the ECU or a sensor ( maybe this ADD ) stopping the ECU sending 12v to the vacuum soelnoids

Paul

[maxigaz]

There should be powered one at the time. I can't recall which one is pulling the add on and which one off. But there should be two wires going to the push switch down to the ADD and telling if it is on. Maybe your ADD turns on and off fine(if you lift both front wheels you can check) but if the computer doesn't get the signal it is on or off the 4wd light will keep flashing. I am not saying this is the problem but you need to check continuity on this one too before step ahead, plus check if the push switch closing the circuit. Send me an email to
*(maxiht@gmail.com)*and I can send some wiring pictures.