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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Kelsfine69 on September 30, 2009, 04:23:26 pm

Title: Air comming out A/C vents when on Heat and Defrost
Post by: Kelsfine69 on September 30, 2009, 04:23:26 pm

I have a 1987 Silverado with A/C. When its on heat I get some air "bleeding" out the A/C vents. Same when I go to Defrost and then when I go to A/C or vent I get more airflow from the dash vents. Is there something I can check without tearing the whole hearter box out? Everything seems to work ok but I dont like warm air blowing in my face when i have the heater on. Thanks

Title: Re: Air comming out A/C vents when on Heat and Defrost
Post by: VileZambonie on September 30, 2009, 07:34:15 pm

Make sure the vacuum hose is hooked up in the engine compartment coming out of the firewall to a vacuum source.

Title: Re: Air comming out A/C vents when on Heat and Defrost
Post by: Kelsfine69 on October 01, 2009, 09:02:54 am

yea like I said everything works but some air comes out the vents when on heat. I wonder if the heater control could be leaking?