1999 gcl ac question

[aukster]

My ac is working but I have noticed that when I'm on a grade going up hill or so that it will cut back some. Would that be a vaccum somewhere doing that or is this normal. Thanks for your help

Auk

[Bob D.]

Sounds like a vacuum leak - the airflow (mode vacuum motor) is moving to the defrost vents, the no/low vacuum default position.
Check the larger sized vacuum hose that connects to the intake manifold.
If there are no vacuum leaks, you may need to install a vacuum check valve on the line.