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After several attempts at trying to repair the HVAC on my '98 c5, I discovered there isn't any vacuum at the vacuum junction box located behind the passenger side glove box. What are the troubleshooting steps and repair procedures for this problem? Any helpful information is greatly appreciated. Thank You.
There are NUMEROUS post on this very topic but, here ya go:
There is a very small NYLON vacuum hose on the very back of the intake manifold. Its a royal pain in the *** to get to and repair. You have to start there and MAKE SURE that its properly connected to the MAP sensor fitting:
From that fitting the nylon line goes into the main wiring harness and down to the passengers fender well and connects to the VACUUM RESIVIOUR CANISTER. Then the line goes through the fire wall to the vacuum control module purple hose.
IF,,,,,,,,,,,, Sometime in the past, battery acid spilled out of the battery and on to the wiring harness/PCM under the battery, that line will dissolve and or crack.
You will need to remove the fender well access panel and inspect all that stuff.
Bill
Last edited by Bill Curlee; Dec 5, 2015 at 10:49 AM.
Started behind the intake manifold. Used a small mirror and flashlight. Everything looked connected. Pulled wheel, inner fender, BCM, and spotted a line that looked pinched/cut (picture attached). Still troubleshooting. Thanks for your advise. Will keep updating until problem is fixed.
Vacuum Problem
