With RPO C60

If the Heater and A/C Control Head appears completely inoperative, perform Chart # 1, "Heater and A/C Control Head Appears Inoperative,". Chart 1 Heater & A/C Control Head Appears Inoperative

Important:
^ Disconnect the negative battery cable for 15 seconds before performing Chart # 2 as this may correct the problem. Chart 2 Heater & A/C Control Head &/or Programmer Inoperative