Diagnostic Aids
WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
- A short to ground or B+ in either the heating element voltage control circuit or ground control circuit will cause both the driver and passenger heated seats to be inoperative.
- An open in the ground control circuit between the module and the splice will cause the seat cushion and seat back the heated seat function to be inoperative for that seat.
- An open in the ground control circuit between the splice and the heating element will cause just that one heating element to be inoperative.
- The following faults will cause a degraded heated seat operation for a particular heating element.
- An open or a short to ground on the temperature sensor signal circuit.
- An open in either the seat cushion or seat back temperature sensor signal or low reference circuit.
- A fault in the temperature sensor.
- A short to B+ on a temperature sensor signal circuit may cause a degraded heated seat operation for both the seat back and seat cushion or just one heating element.
- A broken wire in a heating element may cause a degraded heated seat operation for that particular heating element.
- When inactive the seat heating control module connects the heating element low side outputs to a common reference point internal to the module which is biased to approximately 3.5 V. The module uses this biased voltage in order to check the high side and low side control circuits for a short to battery or ground before enabling the driver and passenger seat heating elements.
- With both the seat cushion and seat back heater elements disconnected, if the high side output of the module is measured it will display a low current 12 V bleed off voltage. This bleed off voltage does not have a meaningful diagnostic purpose. With one or both of the heater elements connected you would just see the 3.5 V biased voltage from this circuit.
- If the heated seats are on high, the temperature level may automatically be lowered after approximately 30 min of operation.