My 4wd won't engage. I think it's a vacuum issue.

rickyd123

I have a vacuum reservoir under the hood. The line that feeds it is unhooked, and I can't figure out where it's supposed to be plugged into vacuum at. I replaced the vacuum actuator on my 4wd, but it doesn't collapse from vacuum when the 4wd is engaged like it should.

rickyd123

My vehicle is a 1995 Gmc Jimmy 4.2L auto. I forgot to put that in my ppost.

thecardoc3

With the engine idling you should be able to hear a vacuum leak. If someone disconnected this on purpose, they might have capped off the nipple. Any manifold vacuum source will be fine if you cannot find the original connection point.

rickyd123

I had to take it to a mechanic. The hose goes at the back of the intake. You can't see it. you have to feel for it. Once the vacuum hose was connected my 4wd worked fine.