A/C-Heater and ATC Control Head

ATC Control Head:

Refer to Heating and Air Conditioning for instructions on how to use the DRB III scan tool or the control head self-diagnostics to test the control head. The problem is not with the control head if no trouble codes are found. The next step should be to check the rest of the system after the A/C-Heater or ATC control head is checked.