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Old 03-21-2010, 05:49 PM   #1
kenm78
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Weak Defrost

My heater in my 82 works good will roast you out. But the defrost is lousy. Hot air comes out of the dash vents great, and when switched to the floor it comes out nice and strong. When you switch it to defrost its nowhere near the flow that comes from either the dash vent or floor. I checked the vacuum valve near the throttle pedal right at the floor heater exit and it is closing all the way when you select defrost just not much air comes out of the defrost vents. I'm tired of slow defrosting. Any help or suggestions would be greatly appreciated. I'm tired of chasing my tail here.
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Old 03-21-2010, 06:02 PM   #2
Stitch
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Re: Weak Defrost

where the defroster duct connects at the bottom inside the dash there might be a gap there...many guys have seen this in their trucks...you can take some a/c metal tape and tape it up and it should fix some of the problem...also, the foam that is between the connection that I'm talking about may also be worn out...
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Old 03-21-2010, 08:02 PM   #3
old Rusty C10
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Re: Weak Defrost

ive had the hoses come off the vents too..other than that its a matter of adjusting the doors if its a n on ac truck
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Old 03-23-2010, 06:38 AM   #4
billnorman
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Re: Weak Defrost

I had an industrious mouse building a condominium in my heater defrost hoses with the seat padding. Also, if stuff from the dash has fallen into the vent housings, it's hard to get air through them. Try blowing compressed air through the ducts with a nozzle to see if crap blows out of them, wear goggles.
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