TP-6811 7/1658 Section 4 Cooling System
4.10.2 Fan Troubleshooting Guide
Symptom Corrective Action
All electric fans are not
operating
Check fan fuses.
Check that fan system positive power supply is properly connected to the positive (+)
battery terminal.
Individual fan is not operating Check fan fuses.
Check fan for obstruction. Check that the fan blades rotate freely.
Check fan motor for open coil (continuity).
Check harnesses from fuse/relay terminal block to fans and controller for damaged leads
or terminations.
Evaluate relays for functionality.
Check for transition at threshold temperatures noted in Figure 4-7.
Overheating: Fan does not
transition to high-speed at
threshold temperature
Check sensor function.
Check harnesses from fuse/relay terminal block to fans and controller for damaged leads
or terminations.
Evaluate relays for functionality.
Check continuity of the coil.
Check for transition at threshold temperatures noted above.
Fans operate in high-speed
mode continuously
Check radiator and enclosure openings for air flow blockage.
Check sensor function.
Check harnesses from fuse/relay terminal block to fans and controller for damaged leads
or terminations.
Evaluate relays for functionality.
Check continuity of the coil.
Check for transition at threshold temperatures noted above.