Part 2 of 2

Chart C-12 Part 2 Of 2:

Cooling Fan Schematic:

Relay Center:

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. 12 volts should be available to CKT 639 and CKT 2 on each relay when the ignition is "ON.
2. This test checks the ability of the PCM to ground CKT 335 (CKT 473).
3. If the fan does not turn "ON" at this point, CKT 409, 532 or 150 is open, or the cooling fan motor(s) are at fault.

DIAGNOSTIC AIDS
If the owner comments about an overheating problem, it must be determined whether the comment was due to an actual boil over, or the hot light, or temperature gauge indicated overheating.

If the gauge or light indicates overheating, but no boil over is detected, the gauge circuit should be checked. The gauge accuracy can also be checked by comparing the engine coolant temperature reading using a scan tool and comparing its display with the gauge reading.

If the engine is actually overheating and the gauge indicates overheating, but the cooling fan is not coming "ON," the Engine Coolant Temperature (ECT) sensor has probably shifted out of calibration and should be replaced.