A/c problem

My a/c blows cold air when first started

then after driving for awhile it will start

to blow hot air. after it sits for awhile

it will blow cold air again.

No simple answer here.
That’s an automatic temp system with sensors and motors and computers oh my.
It apparently believes it to be cold enough after the initial cylcle and isn’t cueing for more.

This won’t be easy nor cheap.

Okay, here’s specific information for your car, not wild guesses. If you have a 2000-2002 LS, then your symptoms are perfectly consistent with a failed DCCV (also called heater control valve.) In the case of the 2000-2002, there is a cold-air bypass door that goes to the non-bypass position after the cabin gets close to the highest of the two set temperatures.

If you have a 2003-2006 LS, then it could still be the DCCV. In the case of these second generation LS’s, there is no cold air bypass door. You would get cold air until the engine warmed enough for the heater to start working.

Failure of the DCCV is common because a small amount of coolant seeps into the solenoid coils that control it and corrode and short out the solenoids. The cost to have the DCCV replaced, including a coolant flush should be around $300.

I disagree. This is a common problem and is not difficult to diagnose. Cheap is a matter of opinion. DIY, it is less than $200.

Thank you so much. Now that I know what the problem is I can get it fixed and not get
ripped off. My car is a 2002 and I appreciate your advice.