I have a 1994 Toyota 4runner, Automatic transmission, 3.0 V6 engine. When I first got it about 3 months ago 4wd worked perfect, engaged quick and easy and all was good. Then my boss and I started moving vacuum lines trying to figure out why it was running bad and I lost 4wd completely without realizing and got stuck stuck. Once I figured out how it worked and that it was a vacuum engagement system I put vacuum to it and it worked but I had to drive like a mile before it would engage, so yesterday I tried to make it faster and bypassed the vacuum solenoids and have vacuum straight to the differential engagement and I cleaned the connector to the solenoid on the differential also. At the connector I got vaguely 6V on one wire and vaguely 12V on the other in 2wd, when shifted into 4wd the 6V went away to nothing but the 12V didn't change. Is that right? I know I have vacuum to it so I don't think its that. Could it be the solenoid that the connector connects to in the differential?

Thanks In advance. Trying to diagnose before winter hits, the whole reason I bought it was for 4wd..

 

The electric connector on the front differential has nothing to do with 4wd engagement.
The vacuum servo does that.
The electrical switch does nothing but light the 4wd indicator light on the dash when the vacuum servo has shifted the ADD collar.

 

You don't give us much to go on, but the "drive like a mile" suggests you don't have the vacuum tank hooked up correctly. This page from the FSM might help: http://web.archive.org/web/201204242...26addcontr.pdf

 

So with vacuum directly fed to the differential the front driveshaft and CV shafts should be connected to each other and the differential should be fully engaged? Also, to verify my indicator works can I put a jumper wire from the two wires in the connector?

 

*Update* FIXED! I had vacuum lines backwards and nonsesne....