Chart C-12B Fans on at All Times

Cooling Fan Circuit:

Circuit Description:
Power for the fan motor comes from a 40A maxi fuse element to terminal "A" on the relays. The relays are energized when current flows to ground through the PCM (Quad-Driver).

Puller Relay - The PCM energizes the relay through terminal "GC4" when the coolant temperature reaches 100°C (212°F) or when A/C is requested.

Pusher Relay - The pusher relay is energized by the PCM if the A/C refrigerant pressure reaches 210 psi (1448 kPa) or the coolant temperature reaches 108°C (226°F).

Chart C-12B Diagnostic Chart:

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks to see if CKT 335 is shorted to ground, which would keep the relay closed at all times.

2. Checks to see if CKT 473 is shorted to ground. A light indicates the wire is shorted to ground the following steps will isolate the short.

3. If the test light is "OFF" after disconnecting the PCM, be sure CKT 335 is not shorted to B +. If not shorted to B +,the PCM is shorted internally.

4. If the test light is "OFF" after disconnecting the PCM, be sure CKT 473 is not shorted to B +. If not shorted to B +, the PCM is shorted internally.