Chart C-12C-A

Chart C-12C-A:

Cooling Fan Circuit:

CIRCUIT DESCRIPTION:
This system uses the PCM, and three relays for control of two coolant fans.

Low Speed - The "LO" speed of both fans is controlled by the PCM. The PCM energizes coolant fan relay "G" through terminal "GC4" when either the coolant temperature exceeds 214°F (101°C) or A/C high side temperature exceeds 122°F (50°C).

High Speed - The high speed of both fans is controlled by the PCM. The PCM energizes all three relays, when either coolant temperature exceeds 226°F (108°C) or A/C high side refrigerant temperature exceeds 149°F (65°C).

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Test light should be "ON" because harness terminal "5" has B+ with ignition switch turned "ON." Terminal "1" has B+ all the time.

2. Test light should be "ON" for 3.0 seconds and "OFF" for 3.0 seconds as EO10 cycles fan "ON/OFF" at 3.0 second intervals.

3. Jumpering harness terminals "1" and "4" bypasses the relay. If fan runs, the relay is faulty.

4. Cycling of the test light proves CKT 1594 and 804 are OK, so fan motor is faulty.