The Heat is on (Always)

[kflo356]

Hey folks, My truck is a 1974 Cheyenne with Factory A/C. I live in Middle TN and it is the middle of summer. The problem here is that my heat is always on. I am looking for a quick fix for the issue and thinking that pulling the fuse labeled "heater" might do the trick. Do any of you know if that fuse impacts any other electrical mechanism in the truck?

I also notice that the moment I turn the key the interior fan turns on. I would guess that another option would be to pull the fuse that controls that fan. At least then it would keep heat from pumping into the cab at the current rate.

Any simple ideas would be greatly appreciated. I don't want to get into any big task yet. Just a simple fix to get me through the summer is the goal.

Thanks

[VileZambonie]

Check the blend door and ensure it is moving when you move the selector to cold. The heater fan comes on when the key is cycled on.

[Jason S]

I put a ball-type shut off valve on the heater hose going to the heater core. I close off the valve during the summer to keep extra heat out of the cab.

You could also just disconnect the power wire at the blower motor.

[roger97338]

My 75 doesn't have AC, so I'm not sure if this will apply to you or not. I was having a similar problem, my heat was always on. Even when I set the controls so there shouldn't have been any heat, there was still heat. Turns out that at some point in the past, some of the cables from the dash mounted heat controller were detached from the levers on the heater, and re-attached to the wrong ones. It was incredibly simple to fix once I realized that was my problem.

[79gmc15]

This is, sadly, normal for these trucks. The fan always runs, the only thing that will work is to cut the low speed wire or hook up a switch to it.

[rustythe4x4]

Hook a switch and a bypass for the coolant, but beware, bypassing the heater core can cause leaks when you pressure it up come fall.