A/C wont blow cold?

[ripptide56]

I have a 2001 silverado 6.0 2500HD. When I start the truck it takes awhile before the a/c starts to blow cold. And also sometimes when I sit in a drive thru or light it will start to blow warm. I have heard of this happening on these trucks but dont know what the problem is? Any Ideas???

[taillight]

It sounds like you are low on R134A. Put on a set of guages and read the pressures.

[ripptide56]

Thanks for the reply. I'm at the correct pressure and amount of 134a..I'm wondering it it's electrical?

[2001jettavr6]

you can still be slightly low on the coolant with the right pressure

[ripptide56]

I did not know that. I'll try putting some more in and see if that cures it!!Thanks

[chuck16]

Also, if your right on with the amount of freon it could be your screen your system. Sometimes they get a little dirty. Though, I haven't heard much about that with these newer trucks.

[wannablast]

My 2001 would do much the same. When I was stopped and it was hot outside it would stop blowing cold air. After I would get the heat out from under the hood it would start blowing cold again. The fix was the low pressure switch. It cost about $35 at the dealer (last summer) and just unscrews. You don't have to worry about pressure loss because there is a valve stem under it that will not let the pressure off when you remove it. I have never had to add freon in the truck and the AC works fine now. (6 years old)

[scottmoyer]

Same here. My old 2001 Z71 had the same issue and was fixed by the low pressure switch. Never had an issue again.