Heater control wiring diagram.

[Mangonesailor]

Hey guys,

I know the heater control units are more of a "universal unit" used in some other trucks and equipment other than just our trucks. Does anyone have a wiring diagram or some sort of technical manual for the heater control units? I would like to modify mine to NOT kick on the A/C when in defrost mode but still be able to cycle the A/C via the push-button.

 

[df2x4]

Sorry I'm of no help but just curious, why do you want to do this? IMO running the AC system with the defroster is one of the most beneficial parts of it, gets rid of humidity in the air so the windshield clears quicker.

 

[Mangonesailor]

Sorry I'm of no help but just curious, why do you want to do this? IMO running the AC system with the defroster is one of the most beneficial parts of it, gets rid of humidity in the air so the windshield clears quicker.

Yet it thaws slower if its covered in ice. I'm pretty well aware of defogging benefits using the A/C.

 

[98_k1500]

Unplug the compressor in the winter

 

[77Impala]

Unplug the compressor in the winter

Or just run 2 wires out to the connector of the compressor from a switch inside the truck so you can stop the AC even if the HVAC control wants to kick it in. I would cut the power wire about 4 to 6 inches from the compressor plug and tie into it. Your second switch would override the HVAC input.

 

[someotherguy]

Or just run 2 wires out to the connector of the compressor from a switch inside the truck so you can stop the AC even if the HVAC control wants to kick it in. I would cut the power wire about 4 to 6 inches from the compressor plug and tie into it. Your second switch would override the HVAC input.

This; once I heard the reason you wanted to do it, the means became extremely clear. But he beat me to it ^^^

Richard

 

[Mangonesailor]

Or just run 2 wires out to the connector of the compressor from a switch inside the truck so you can stop the AC even if the HVAC control wants to kick it in. I would cut the power wire about 4 to 6 inches from the compressor plug and tie into it. Your second switch would override the HVAC input.

This; once I heard the reason you wanted to do it, the means became extremely clear. But he beat me to it ^^^

Richard

Good thing I bought that weatherpack connector kit. I'm R&D'ing a switch panel for the Fog light "blank" in the truck now. I can just add a push-button there.

I would still like to control it from the HVAC unit to keep it just that much cleaner. I guess I can grab one from a junkyard and rip it open and probe it. Come to think of it, my shop manual should have a diagram.

 

[someotherguy]

Schematics of the controller in the factory manual? Haven't seen that. Usually seems like they stop at depicting it as a mysterious box at the end of a wiring diagram. But the newest factory manual I've got is 1994...

They want the customer to buy a new control unit, not have the tech troubleshoot the piece. That said, if you've seen schems, I'd sure like to see them too.

Richard

 

[98_k1500]

Maybe a tahoe unit with a rear defrost button wired where it cuts the ac clutch power via a relay. You could then push the "factory" defrost button to enhance the de-ice process?