Electric Cooling Fan Diagnosis

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The relay coils are energized when the PCM completes the ground path. The PCM Output Driver Module (ODM) B output 1 is grounded for Fan 1 operation.

During Fan 1 operation the PCM supplies a ground path for the Fan 1 relay through ODM B Output 1. This closes the relay contacts and current flows through the relay and to the cooling fan. The primary cooling fan is grounded at the engine block.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table:

2. Stored Diagnostic Trouble Codes (That may not illuminate the Malfunction indicator Lamp) may enable the engine cooling fans. This Diagnostic Table may lead to improper diagnosis and replacement of good pants if Diagnostic Trouble Codes are present.

5. Ambient temperature must be above 9°C (48°F) before the PCM will enable the cooling fans due to A/C request. The PCM will enable the cooling fans if A/C refrigerant pressure increases regardless of ambient temperature.