Positive Temperature Coefficient Heater Unit

Positive Temperature Coefficient Heater Unit


Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions may result in accidental airbag deployment and possible serious or fatal injury.

• Refer to for circuit descriptions and diagrams. Wiring Information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

Prior to replacing the positive temperature coefficient heater unit, check for any DTCs related to the PCM, TIPM and the heating-A/C system and repair as necessary. Also, run the calibration procedure to verify that the concern is not a heating-A/C system issue. Refer to => [ HVAC Actuator Calibration Procedure ] HVAC Actuator Calibration Procedure.

- Disconnect and isolate the negative battery cable.

- Disconnect the wire harness connector from the PTC heater unit.

- Using an ohmmeter, check for continuity between ground and the PTC heater. There should be continuity. If OK, proceed to the next step. If not OK, replace the PTC heater and air distribution housing as an assembly.

- Using an ohmmeter, check for continuity between all of the PTC heater unit wire harness connector terminals. In each case there should be continuity. If OK, repair the wire harness circuits between the PTC heater unit and the ECM and the TIPM. If not OK, replace the PTC heater and air distribution housing as an assembly.