I've got this strange problem that I think is a vacuum leak but I want ya'll to tell me that before I start tearing things apart. I can turn the key on and only get air to blow out of the heater vents (switch doesn't work but the blower is going). As soon as I start it, I can switch between all settings and sometimes it takes a few seconds to blow from a/c to max a/c. Sound like a vacuum leak? And where should I start looking and what should I be looking for? Thanks.

 

I think I'll have to answer my own question on this one. I looked at my service manual last night and it looks like it's a function of the vacuum check valve. It states that the valve is supposed to keep a vacuum on the switch so it won't default to the defrost when the engine stops. Hopefully I won't be throwing parts at it but if it's not too expensive, I'll try this first.

 

Would the vacuum leak also cause the AC not to blow out of the vents. My AC will mainly blow out of the defroster vents and occasionaly out of the head vents only during accelleration, but only a for a few seconds. Mabey I will start a new thread. Thanks

 

You are correct sir! I decided not to replace the check valve when they quoted me $175 for it. I went and bought a Mighty Vac and traced my problem to a broken vacuum line. When I had the vacuum system "open", only the defroster would work.

And by the way, welcome to DTR!