SYMPTOM RELATED DIAGNOSTICS

ON/OFF FAN CONTROL VERBAL COMPLAINT (continued)

Test 129

Checking for a short to ground between the pressure switch and the module

Test 256

Checking for a pin-to-pin short

1.If a manual override switch is used, set the switch to the OFF or normal position.

2.Disconnect the serial link jumper.

3.Disconnect the harness at the freon fan pressure switch.

4.Check for continuity from J1B connector pin Y2 (the Auxiliary No. 1 output line) to a good ground.

If there is continuity, there is a short to ground between the freon fan pressure switch, override switch (if used) and the V-MAC II module. Locate and repair the short to ground. Retest to be sure the problem has been corrected.

If there is no continuity, there is an open at the freon fan pressure switch connector, or between the freon fan pressure switch, override switch (if used) and the V-MAC II module. Locate and repair the open. Retest to be sure the problem has been corrected.

1.Disconnect the serial link jumper.

2.Disconnect the engine harness from the fan clutch solenoid connector.

3.Disconnect the J1A and J2 connectors from the V-MAC II module.

4.Check for continuity between J1B connector pin Y2 (the Auxiliary No. 1 output line) and each of the other pins (one at a time) on the J1A, J1B and J2 connectors.

If there is continuity with another pin, locate and repair the short to pin Y2. Retest to be sure the problem has been corrected.

If there is no continuity, proceed to Test 512.