Expert: Skip Bollinger - 4/20/2008

Question
QUESTION: I hear a loud click when I rotate the funtion button to the defrost position, however if I move it back to just blowing air in the cabin the sound goes away.

I am not sure if they are related but I remember last summer hearing a similar noise while turning the A/C on and off.

I just replace the resistor for the blower and this doesn't fix it.

Is it the compressor? Blower?

Thanks

ANSWER: G.
 I am a Parts Specialist, NOT a Tech but will off these thoughts for you to ponder.
 Your mail is a bit confusing. At first you say you hear a "loud click" when you place the selector in the "defrost" position. Then you say that when you move the selector to "just blowing air"..."the sound goes away". One statement leads me to believe the noise is momentary and the next statement leads me to believe the noise is ongoing. I'm confused. Regardless...
 I'm going to guess the noise in in the diverter door area under the dash. From the information you have provided, it has nothing to do with the compressor or blower. You may have to get on your back on the front floor board to pinpoint the noise. You may need to have someone else move the selector while you listen for the noise.
 I'm sorry I'm NOT a Tech. IF I'm wrong, don't hammer my chops. I'm just trying to give you some direction. This is something that can be expensive to repair. It isn't the price of the part but the time it takes to get the dash apart to get to the part. Good luck...
Skip

---------- FOLLOW-UP ----------

QUESTION: Reading more about my problem I am more incline to believe that I have a leak on my A/C system. Moving cursor to the defrost position requires help from the A/C compressor to clear the moisture from my cabin but because I might not have any freon the compressor stop working thereofre the noise. If I just blow air in the cabin there is no much of a noise at all.

Am I on the right track?

Answer
G.
 If the system has no freon, there is a "low pressure switch" that keeps the compressor from coming on. If it has no freon AND oil, it will self destruct. It is a self preservation system designed for the compressor. No freon, no oil no work..
 I can't understand how you can think the compressor is not working but making a noise...???
Skip