The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

69GMCLonghorn · 12-03-2009, 03:16 PM

Luckily, the heater systems are not overly complicated on these trucks so it can only be a handful of things causing the no-heat-freezin'-your-n*ts-off syndrome. I spent one day going through mine a few years ago and had PLENTY of heat, even when it was 30 something outside (yes, it gets down there in the SF valley a couple times a year!).

Check that the barn doors are actually opening and closing by moving the butterfly valves, not the cables.

Clean the crap out of the heater box and make sure that leaves are plugging up the air flow.

Is the fan coming on? If not, check the motor, connections, fuse, etc...

There shouldn't be a heater control valve in the cooling system (assuming it's non-A/C), but if someone snuck one in, that might be an issue as well.

12-03-2009, 03:16 PM	#9
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: heater isnt heating anything Luckily, the heater systems are not overly complicated on these trucks so it can only be a handful of things causing the no-heat-freezin'-your-n*ts-off syndrome. I spent one day going through mine a few years ago and had PLENTY of heat, even when it was 30 something outside (yes, it gets down there in the SF valley a couple times a year!). Check that the barn doors are actually opening and closing by moving the butterfly valves, not the cables. Clean the crap out of the heater box and make sure that leaves are plugging up the air flow. Is the fan coming on? If not, check the motor, connections, fuse, etc... There shouldn't be a heater control valve in the cooling system (assuming it's non-A/C), but if someone snuck one in, that might be an issue as well.