this is a weird problem. when I am running the air conditioner and need to go to heat the next morning when it is cold, there will be no heat coming out till I lower the temp buttom all the way down to low and then all way back up to hi, then the heat will start working, any ideas on what is causing this?

 

what kinda car is this first of all

 

sorry, its a 1999 LHS

 

either the ac control head is having an issue or the BCM Body computer is having an issue

 

Blend Door hanging up or actuator is failing. Test the ATC with the following proceedure

RECALIBRATING YOUR AC:
1. Start the engine but do not move the vehicle.
2. Set the Temp control to 75 degrees.
3. Press and hold the Floor, Mix (vent/defrost) and Defrost buttons at the same time. The floor is a bottom button and the others are upper.
4. The control head will begin to blink and enter a diagnostic mode.
5. Release the Floor, Mix and Defrost buttons.
Once the unit has gone through its diagnostics it will either return to its normal mode (with all air doors calibrated) or it will return one or more of 16 different error codes between 23 and 51. The ATC control can only show one diagnostic trouble code at a time. Under certain circumstances, more than one diagnostic trouble code could be in the memory. To scroll through any additional diagnostic trouble codes, press the Panel Mode button on the ATC control. Any other button or turning of a **** will end the diagnostic test without showing the rest of the trouble codes.
This will calibrate and set up the blend door.



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Code 23 would be the blend door actuator.

 

thanks I tried and got a code 23. went to pic and pull and got a blend door actuator. will install this weekend.

 

Sounds like a plan. Aftermarket (Dorman) have a poor track record of success, so a used one is what I have used......