Chevy & GMC Vans

Originally Posted By SOCALLI V8

Here are the heating /ac vacuum diagrams for the `85-`94 Astro

Well I just had my doghouse off yesterday. I haven't had it off for a few years. Some major work done by mechanic and they worked under there. Well I could not believe how cramped it was. One repair I had done was head gaskets since the pastic ones GM put in a prone to leaking by the A/C compressor mounts.

I was looking to see the state of the vacumn line replaced 4 years back that controls the vent/foot/defrost selector. Well I could only find one coming back behind the oil fill pipe which went toward the rear heat solenoid area. I was under there with my 2 million candle power lantern. I even managed to get the doghouse right out of the footwell area (an almost impossible feat I'd say without taking out a seat). Still nothing else to see. Barely enough room for my body.

The diagrams above must be entirely different on a 96 Astro W block LT model but certainly would be helpful if someone comes across one. Pulling the doghouse out is serious endevour and not one to do often.

I still thinking of finishing the + power run from the alternator for the Big Three wiring upgrade but can't get at the back of the alternator. I will have to pull the whole breather system out at least and hope not to short it out. For this I would certainly disconnect the battery first but maybe a retrofit for the block on rails like server. Slide it out, service it and slide it back in is needed.

Good to find this info. a year and a half later. Thanks for posting.

I have the diagrams for the 96+ floating around here somewhere I'll post em up for ya when I find em.


Edit ok I found it but it's in PDF format and it's from a 98 FSM so it may not being exact but it's almost definitely closer than a pre 96. Fire me an email at potskie A T Hotmail.com and I'll send it to ya.

Any chance you have the diagrams for the engine vacuum? I have a few missing lines and such I need to replace but I don't really know what goes where and my haynes manual does not have it.