Here's the deal. AC runs great sometimes...and other times it won't turn on at all.

I checked and have about 55 lbs of freon in the system so that should be cool.

There is a sensor on the side of the "silver tank" by the blower. Yeah, not very technical but wait...there are pictures :-)

If I disconnect that sensor wire and plug it back in....system will sometimes run for a few minutes then shut off...might come back on later..hard to tell.

If I disconnect that sensor wire and jumper it (picture attached) the AC blows cold for as long as it is jumpered.

What is that sensor? Assuming it is bad and I replace it...I am guessing I need to evacuate and recharge the AC system yes?

thanks,

Will

 

That sensor on the side of the can is a pressure safety switch. If the pressure gets too low it shuts off the compressor so you don't smoke it due to a lack of freon. Try adding a can, I think that would cure your problem.

 

I added a can and it didn't fix the problem. I am at 55 lbs which is the upper range (40-55) for being 90 degrees outside. So says my test kit.

If I replace that sensor do I have to evac/recharge the system? I am betting yes.

 

Hay Renthorin, thanks for informing me on your thread. Alright, I went out and did the same thing with the jumper wire as you did and my compressor kicked on but my a/c guage is saying the system is full of freon. What now??? Please keep me updated and thanks alot.

 

I am guessing that sensor has gone bad and it telling the system low or no freon. Hence the sometimes it works...sometimes it doesn't.

I wonder if anyone else has had this problem and replacing it solved it???

I don't know if there is a danger jumping the wire like I/we did. Of course if your system runs out of freon that would be bad but we both have plenty. I assume should a leak develop it wouldn't blow cold anymore so that would be an indication.

I just hate the thought of pulling that sensor and having to recharge the system :-(

 

If you remove the sensor you would have to evacuate and recharge, when you have that sensor jumped is the pressure staying at 50 or is it dropping down to like 20?

 

it stays at 50, or at least did for the 25 seconds or so I watched it.

 

(reads the wisdom above). Bummer, I always thought they would fail as an "all or nothing". Intermittent will drive you nuts.

 

Oh it is definitely doing that. One day it works fine...the next day either nothing at all or only a few minutes.

I unplugged and cleaned the contacts and that seemed to work for a while but today it shut off again after 10 minutes or so and wouldn't come back on.

I need to find out how much the sensor is...and the cost for evac/fill...and weigh that against leaving it jumped for the rest of its life and crossing my fingers.

The truck only gets driven once or twice a month and sometimes not at all. I use it for when the roads are crappy (winter) and for camping but that's it.

Might last a long time jumped at that rate :-)

 

Hay Renthorin, go start up your blazer turn the a/c on and get a large screw driver and tap the silver part of the switch on the side of the can and see if your clutch ingages. Mine did.