.....?

 

I think that its called transfer indicator switch or something like that. I could be wrong but isnt it the same switch that is on the transfer case??

try this

http://www.toyodiy.com/parts/q.html

 

My fsm call it a 'ADD indicator switch'

 

Thats what I thought. I had to short this to get my 4x4 to work. I think my 3.4 ecu didnt have ADD.

 

My problem with the ADD is that it was vaccum and the 3.4 doesn't have vaccum so I'm, putting manual hubs in.

 

your 4x4 will still work wont it? I thought just the light in the dash wouldnt work

 

On my swap, ORS wired the indicator wire to the transfer case. I can't help you much, unfortunately, since I didn't build my harness, but it does go to show you don't need to wire in the indicator on the diff. As for the vacuum to the vsv, check out my thread...I may have a clear picture of the routing, and I used the original vsv's for my 3.0.

https://www.yotatech.com/forums/f160...eknraj-161816/

Sorry, I'd post the pictures if I could, but work computer blocks photobucket.

 

Yeah which I'nm not worried if it says that its in 4x4 or not, cause I would have just locked it in and kinda would remember that. I don't need all those lights telling me what I'm doing.

 

The wiring for this is really easy actually. The power for the system comes through the bulb, so you do need the 4x4 dash light in the circuit. The wire from the bulb goes to the 4x4 switch, then a wire from the 4x4 switch goes to the switch on the front diff, then the other wire on the diff switch goes to ground. At the join of the 4x4 switch to diff switch, a third wire goes to the coil of the add relay. Output of the relay goes to the 2wd and 4wd vsv's and thats about it.
Short the wires together for the diff switch and you dont need to connect the ecu.
Basically the 4wd shifter is the only switch now and it activates the relay.

If this makes zero sense, I'll search and post the schematic.

 

This makes no sense. If your engine has no vacuum then its either at WOT, off, or has about 2psi of compression in each cylinder.

Care to elaborate?

 

UK runner, Can you post the schematic that you mentioned? I have an ORS harness but it doesn't have the plug for the diff and I want to have my ADD fully operational. Also, where do you get the vacuum source from on the 3.4?

 

Looking for it... will post when I find it.

 

Thanks, I look forward to figuring this part out. Next will be getting my R12 system to fit and work...

 

Send me your email and I can send you the pdf now I've found it.

 

I can't believe I missed this in my research. I didn't think the ECU had anything to do with auto hubs. I guess the VSV feeds a status back to the ECU?

Does that mean if the 93 chassis had auto hubs that the donor ECU must come from vehicle with same?

thanks

 

I dont think my ecu came from a vehicle with auto hubs because when I connected my ecu, nothing happened. I removed the connection to the switch on the diff (shorted it) and now the 4x4 works perfectly.