Cooling Fan System
- Connect a test light to battery voltage. Probe test light to cooling fan control driver terminal of PCM. See Figure & Figure . Disconnect coolant temperature sensor. This should set a code, causing PCM to engage cooling fan through relay. On some models, it may be necessary to jumper the coolant temperature sensor harness connectors. On some models, grounding the DLC with ignition on and engine off will cause PCM to activate cooling fan control driver (ground circuit).
- If test light illuminates and cooling fan does not come on, check cooling fan relay, power circuits, cooling fan motor, and relay and fan motor ground circuits. If test light does not illuminate, problem is a faulty PCM connector or PCM. Clear diagnostic trouble code(s) from PCM memory after testing.
- If cooling fan functions normally during testing but fails to operate under normal conditions, check PCM monitored inputs which affect cooling fan operation. These include the following: coolant temperature sensor, A/C request signal from A/C control switch and A/C pressure sensor, or pressure/temperature switch signals (if equipped).