I live in a warm climate. When the climate control is set to 72 degrees, the cabin will cool to 72 degrees and the fan will slow down as it should. For the next 25-30 minutes, the climate control will correctly maintain 72 degrees. After that time, the air flow temperature increases, the fan stays at a slow speed and the cabin temperature increases significantly.

The dealer refuses to make any repair because there is no fault code. Obviously something is wrong such as the temperature sensor.

Any thoughts?

Has the dealer attempted to replicate the issue?

The dealer claims to have rod tested the vehicle.

Did they observe the behavior?

The dealer claimed it couldn't replicate the behavior, although I don't believe the dealer tried to. The bottom line, after leaving the vehicle at the dealer for three days, was the dealer'* refusal to replace any parts or make any adjustments because there was no fault code.

You don't want that one. Tell them you want another one. Keep all your receipts in case.

I forget, does this car have an engine-hours meter?

It would be interesting to discover that it has the exact same hours on it as when you dropped it off after they supposedly attempted to reproduce the issue.

In the end, they need to see the problem before they can do anything about it.

Can you reproduce the issue at idle in a parking lot? If so, take it back to them and reproduce the issue right in front of them.

Or find another dealer that is more helpful.

GM Tsb #21-NA-248 deals with intermittent loss of a/c caused by contamination in the A/C refrigerant. This TSB is VIN specific. Your local dealer can look it up and see if it applies to your vehicle.

Yeah, I agree, you don't want that one.