Heater Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

eightbanger · 02-26-2008, 04:06 AM

When I bought my truck the heater would divert air to the windshield when deice was selected and to the foot well when needed there, but now it will only blow air through the diverter balls and the center vent, this happened only recently, the A/C does'nt figure in the problem as all the vacum stuff and hoses had been removed before I bought the truck. I have taken all the heater control stuff out and checked all the various cables and diverting doors inside the heater boxes under the dash and everything is opening and closing fine when I slide the selector knobs on the control panel. I can't figure it out, did I hear somewere that these trucks have a heater thermostat in them that doe's something when the cab gets to a certain temp?? if so maybe it's broke.

JimKshortstep4x4 · 02-26-2008, 04:36 AM

Usually the diverter box door does not move when this problem occurs. Check the door carefully as they break where they are connected to the shaft so the shaft moves but the door does not.

Jim

eightbanger · 02-26-2008, 04:46 AM

I did look at that door and will say although it moved up and down it was weak on the hinge part that you described. I hope it's gonna be that simple a prob.

Thanks Jim.

02-26-2008, 04:06 AM	#1
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Heater Question When I bought my truck the heater would divert air to the windshield when deice was selected and to the foot well when needed there, but now it will only blow air through the diverter balls and the center vent, this happened only recently, the A/C does'nt figure in the problem as all the vacum stuff and hoses had been removed before I bought the truck. I have taken all the heater control stuff out and checked all the various cables and diverting doors inside the heater boxes under the dash and everything is opening and closing fine when I slide the selector knobs on the control panel. I can't figure it out, did I hear somewere that these trucks have a heater thermostat in them that doe's something when the cab gets to a certain temp?? if so maybe it's broke. __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger

02-26-2008, 04:36 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Heater Question Usually the diverter box door does not move when this problem occurs. Check the door carefully as they break where they are connected to the shaft so the shaft moves but the door does not. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

02-26-2008, 04:46 AM	#3
eightbanger 454 MAKES IT ROAR Join Date: Jan 2008 Location: Essex, U.K Posts: 2,701	Re: Heater Question I did look at that door and will say although it moved up and down it was weak on the hinge part that you described. I hope it's gonna be that simple a prob. Thanks Jim. __________________ Nigel. An American living in a British body. 1971 Chevy Cheyenne 10 454 "In a time of universal deceit, telling the truth becomes a revolutionary act." - George Orwell "When injustice becomes law, resistance becomes duty" - Thomas Jefferson No more pain. 03.12.60 -- 12.28.10 http://www.youtube.com/Eightbanger



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