Radiator Cooling Fan Motor: Testing and Inspection

ELECTRIC COOLING FAN





The Powertrain Control Module (PCM) will set a Diagnostic Trouble Code (DTC) in memory if it detects a problem in the electric cooling fan , relay or circuit.
The DTC can also be accessed through the DRB scan tool.

RADIATOR FAN MOTOR INOPERATIVE
Equipment Required:
^ DRB Scan Tool
^ Volt/Ohm meter
^ Wiring Diagrams
Test Procedure:





1. Inspect 10A fuse in junction block and 40A maxi fuse in PDC.
2. Remove Cooling Fan Relay from the PDC and make the following checks at the relay connector:
^ Apply 12 volts (using a fused 14-gauge wire) to circuit C25 (relay terminal 87). If fan does not come on, check for open in circuit C25 or Z1. If circuits are o.k, replace the cooling fan motor.
^ With the ignition key "off" check for battery voltage at circuit C28 (relay terminal 30). If no battery voltage present check for open/shorted circuit C28 between the PDC and relay.
^ With the ignition key in the "run" position check for battery voltage at circuit F18 (relay terminal 86). If no battery voltage present, check for open/short in circuit F18 between the junction block and the relay.
^ If no problems are detected, install the DRB and start the engine. Clip a 12V test light to the battery positive terminal and probe circuit C27 (relay terminal 85). When the engine temperature reaches 110°C (230°F), or A/C is requested, the test light should light. If not, check circuit C27 for open.
^ If no problems are detected at this point, replace the cooling fan relay.