© Copyright 2000 Frank Zemaitis/STE, ltd. All Rights Reserved
This seems to be a very common complaint when the first warm days of the new year come around. Commonly this is a vacuum problem without any one particular cause or fix. Any leak in the vacuum system can cause not only problems with the heating and air conditioning, but other engine performance related problems as well. Check the 2 vacuum lines at the fire wall on the passenger side for cracks and leaks.
One goes through the fire wall and supplies the climate control solenoid array with vacuum. The other vacuum line controls the water cock.
These 2 vacuum lines run back along the fender well to the vacuum canister. Check all of these vacuum lines for cracks and leaks.
If they seem hard and brittle I strongly suggest replacing, not just these, but ALL vacuum lines in the car. Looking closely at these lines you will find that all or most are color coded with a stripe. At the canister there are 3 vacuum lines with a blue, white and red stripe. You may not have to trace every inch of vacuum line to replace it if you can find both ends of the color coded ones. Once you have identified both ends run a new line and pull the old one out or just leave it in. This may or may not fix the particular problem you are experiencing. The problem can be behind the dash in the heat/AC unit or the control unit.