Whenever I have to sit for a few minutes at the red light, ive noticed my ac will get warmer and warmer. Once I get going it cools down. Yesterday the light was out and I had to sit through it for about 5+ minutes, during this time the AC was so warm I had to turn it off. It seems that it runs cool once I get air blowing over the condenser.

I have AC gauges but Im not sure what this truck is suppose to have in 100 degree weather on the High and Low side at idle. Does this sound like low coolant?

 

Here's a thread with a LOT of useful info.

Tony

 

fan clutch

 

Agreed, probably what it is. If the fan was working properly there would always be air flowing over the condensor keeping the compressor from disengaging due to high pressure.

Do you have any codes?

 

no codes, im assuming if the fan clutch is bad at 40k then it wont spin when its warm at idle?

 

Ummm...No...if the fan clutch is bad, it either won't engage, or stays engaged all the time.

Tony

 

It should spin all the time but it will not match the engine speed unless its electrically engaged by the ECM. You know when it is engaged our fans can move a lot of air and are noisy. Mine will cyle on/off at idle with the a/c on and engine at normal operating temp.

 

It's most likely just low freon. Always step 1 on these trucks

 

i can hear the air moving until i get to about 40 mph.

What is the correct lbs I should see on the gauges?

 

the fan is working properly.

I hooked the gauges up and noticed that when the compressor is on it reads 55/450 in 100 degree weather.

The compressor cycles on and off, im not sure why. Do these values seem high?

Of course when the compressor cycles off the pressure raises to about 70 and lowers on the high side and then comes back on again

 

it cycling from low freon. If you can add some you'll see the low side go down and the high go up. That compressor should be staying on in this heat

 

the cool side gets down to 55 then the compressor kicks off and of course the low side rises. What is the target low side lbs in 100 degree weather?

 

about 40. add and it will drop