A/C wont blow cold?

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???

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

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

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

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

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.

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)

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