Amish hauler

Today I noticed I didn't have the best heat or defrosters. When I got home I decided to change my fuel filter and I noticed My A/C tank and Lines were frosted white with ice. I replaced my filter and test drove the truck ( hoping for more power) and had no heat or defrosters. So I unplugged the plug on top of this silver tank on the fire wall and after a few miles I had heat again.
I looked and sure enough the tank and lines were thawed out. So thinking I must have fixed it I plugged it back in. In a couple of miles the same thing happened..?? All frosty and no heat. Am I low on freon or something??

duner

sounds like something has your compressor running when it shouldn't be

Monty

I believe that switch you refer to is the pressure switch which sends a signal to the compressor and fan. Fathers 98 froze up during the summer and the a/c relay would kick off. The problem was fixed by a new switch.

DRD

Yup, sound like the pressure-cycle switch is no good.

Smokee

The pressure switch is an inexpensive fix. I think that a GM switch will fit, also.

If you are changing the switch yourself, have the truck running and the AC turned on. There is a little ball or something that can be lost.

Amish hauler

Is this switch the one that I unplugged? It is located on the passenger side fire wall on top of a stainless or alum. canister with the a/c lines running to it.?
And Thank you for your time.

Smokee

Yes, that is the switch. If I remember correctly, it is yellow...at least mine was. You do not have to drain the system to change it. I had mine done at an AC place in Florida, and they checked the whole system, recharged, put in leak detector, etc. for about $80.

Good job

EastCarolinaRam

Check your thermostat, probably hung either open or closed, just replaced mine for around 60 bucks

Stamey

That thing you unplugged was on the Filter Dryer. See pic. Mine's black.
Now, I don't know about running the AC when changing out that switch. All of them I have seen are directly plumbed into the AC system because it's a pressure switch. When you take it loose, if you haven't already, you'll evacuate that AC system pretty quick. I could be wrong, but keep it in mind until you know absolutely.

The reason the AC is stuck on could be that switch, or it could be another switch in the system. There are a few.

FYI: The AC Compressor runs on the vent/heater, defrost, and the heater/defrost settings, besides the actual AC settings. Weird behavior as far as I am concerned, but that's how they did it.


Chris