HVAC Air flow - always some defrost - Chevy Impala SS Forum
 
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post #1 of 4 (permalink) Old 05-03-2017, 09:59 AM Thread Starter
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HVAC Air flow - always some defrost

I had the A/C on this morning as I drove into work, and it seemed as though every position is allowing some air to come out of the defrost area. Therefore I had to use the wipers to get rid of the condensation on the windshield.

Before I go digging into things this weekend, I thought I'd post this to see if anyone has a similar experience and what to look for?

I'm assuming it may be a vacuum line may not be making a good seal somewhere....

Thx.

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post #2 of 4 (permalink) Old 05-03-2017, 10:15 AM
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There will always be a slight amount going to defroster,as it is part of the default to the HVAC system... More than that,I suspect one (or,more) of the blending doors is not closing all the way...

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post #3 of 4 (permalink) Old 05-03-2017, 10:23 AM
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I had that exact symptom, and it was the vacuum line. I would check the engine area first. If your vacuum to the selector valve under the dash is good, check the vacuum motor that works the defrost diverter, and the line that works it. It is also possible that the check valve is not working.

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post #4 of 4 (permalink) Old 05-03-2017, 04:12 PM Thread Starter
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Thanx for the info. I suspect I may have accidentally pulled a vacuum hose or done something when I was installing a new/old radio in the car last weekend.

Saturday will be a busy day...

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