Chart C-12A, Cooling Fan Circuit Diagnosis 3.8L: Overview
NOTE:
Test numbers refer to numbers on diagnostic charts.
- Checks if circuit No. 335 is shorted to ground, keeping relay closed at all times.
- Checks if circuit No. 473 is shorted to ground. An illuminated test light, indicates wire is shorted to ground.
- If test light is off after disconnecting PCM, ensure circuit No. 335 is not shorted to B+. If circuit is not shorted to B+, PCM is shorted internally.
- If test light is off after disconnecting PCM, ensure circuit No. 473 is not shorted to B+. If circuit is not shorted to B+, PCM is shorted internally.
NOTE:
Test numbers refer to numbers on diagnostic charts.
- Checks for battery voltage at relay harness connector.
- Jumpering cooling fan relay terminals "A" and "E" by-passes relay, causing fans to operate, if fan motors and wiring are okay.
- Grounding test terminals should cause PCM to ground circuit No. 335. At this point, test light should illuminate, if PCM is good and circuit No. 335 is not open.
- Checks for battery voltage and ground to fan motor. Test light illuminated at this point indicates a faulty fan motor connection or motor.
NOTE:
Test numbers refer to numbers on diagnostic charts.
- Test light should be illuminated because harness terminal "F" has battery voltage with ignition in ON position.
- Jumpering relay harness terminals "A" and "E" by-passes relay. If fan runs, relay is faulty.
- Checks circuit No. 473 back to PCM. If circuit No. 473 is okay, relay is bad.
- Checks wiring to cooling fan motor. If wiring is okay, problem is in connections, motor or motor ground.