Jim is right, your A/C may not be cutting out, if the duovalve is doing it's usual "stick open" thing, then once the engine gets hot, you have heat, even if the A/C is cooling the air, it then goes thru the heater core and if the valves are open, you get hot air.


The issue can be a sticky valve or valves OR it can be fractured solder connections between the two circuit boards of the climate control module in the dash.