Problem with 1999 Chevy Monte Carlo A/C?

Question

The A/C on the Monte Carlo when going up a hill or if you step on the gas hard it swiches from the front vents to the windshield defroster it really ticks me off in the summer. Any idea of how to fix the problem?

Answer 1

Yeah vacuum leak.

Had a '95 Z34 with the same problem that's real fun to fix.

For some reason this is common in the monte carlos, and even more in blazers.

Answer 2

you have a vaccume leak. possible causes are the vaccume canister located under under one of the ft fenders.a vaccume line or the vaccume acuator that keeps the vent door in position is leaking.a hissing noise would also be an indication of a leak