Has anyone else noticed that whenever the A/C cycles like when you have the defrost on to clear the windows and the truck is ice cold that the high temp fan will cycle on and off repeatedly?

I hooked the green controller wire up as stated in the directions so it would come on with the A/C in the summer. I assumed that is the only time it would come on besides hitting the high temp I set the controller to. It is full on winter here and the fan cycles on and off when the truck is ice cold just because I have the defrost on to clear the windows .

Does everyones elses do this too?

 

Mine does it too. I'm not 100% certain but I think that most cars now run the AC to keep the compressor and seals lubed up when the defroster is on. Basically running the system so it doesnt sit with out working over the winter.

 

All new cars do cycle the compressor when the defroster is on for the purpose you stated.

I would have thought that there would have been a way to hook the high temp fan to come on only when the actual A/C was being used and not when it was cycling for the defrost. Having the fan come on and off that often when it is -28 degrees Celcius outside seems insane to me and a quick way to burn up the controller. When it is that cold I need the defrost on to drive so the windows don't fog/ice up. It is going on and off all the time.

I think I will add a quick connecter in the green wire so I can just unplug it for the winter.

 

You are correct that wire is the wire to your compressor so everytime it comes on your fan is going to come on, I've got an easy fix though just move to Florida and you wont have to worry about the defrost

 

I wish. I love the sun and hate the cold.

Golfing all year-round.

Maybe someday.

 

Compressor comes on and the freon flows to dehumidify the air. Dry dehumidified air clears a windshield much quicker than ambient or damp air, reguardless of temp. Take a cool rainy day, no contest.

My '77 F150's AC / heater was factory set up to defrost without AC compressor on. I added a togle switch to toggle it on at will, and the difference is like night and day when demisting the windshield.

 

Just noticed mine did the same thing. Its funny when idling and suddenly it sounds like a jet engine getting ready to take off.