4WD stopped working. Still have both high and low range, just no 4WD. Checked diaphragm and no vacuum to it with either 2WD or 4W button lit. Cable moves freely. Can't find where the vacuum line goes. It disappears behind engine at firewall. Working on ramps so visibility is lousy and I may be missing the obvious. Maybe related, getting Code 441 for emissions which might mean a vacuum
leak. Fixed all leaks that smoke test showed. Car does run ok. Questions are: 1) where is the vacuum solenoid?
2) Where is the source for the vacuum that the solenoid would turn "on".

 

On drivers side. Right on top of transfer case. 3 vacuum lines run to it. 1 is vacuum line from manifold.2nd is a vent that runs up trans tube. 3rd runs to under battery tray.

 

Thanks. It was hard to spot with skid plate blocking view. Now to find out why no vacuum at the solenoid.

 

It gets vacuum from the intake manifold. Drivers side valve covers there is a PVC tube follow it up to 3/8 elbow and vacuum line(BINGO). Thats where it comes from. Follow it to a check valve T. One side goes down firewall to the transfer case switch. You should get 20" of vacuum at that check valve T start there. GL