Cooling Fan Not Working
A cooling fan that does not run can make the engine overheat at idle or in traffic while temperatures may improve at highway speed.
Can I Drive?
fix-soon
Most Likely Causes
- 1
Blown fan fuse or bad relay
The fan circuit may not receive power.
- 2
Failed fan motor
The motor can wear out, develop dead spots, or draw too much current.
- 3
Bad temperature sensor input
The computer may not know the engine is hot enough to command the fan.
- 4
Melted connector or wiring fault
High fan current can damage terminals and wiring.
How to Diagnose It
- 1
Command fan with AC or scan tool
Many vehicles run the fan with AC on; a scan tool may command it directly.
Tool: Scan tool if available
- 2
Check fan fuse and relay
Verify power through the fuse and relay rather than only looking at them.
Tool: Test light or multimeter
- 3
Inspect fan motor connector
Look for melted plastic, loose pins, or blades that do not spin freely.
Tool: Flashlight
How to Fix It
Repair fuse, relay, or wiring fault
Replace failed electrical parts only after checking for motor overcurrent or shorts.
Replace failed fan motor or assembly
Replace the fan if it fails direct testing or current draw is excessive.
Repair temperature input issue
Fix coolant sensor or wiring problems that prevent fan command.
Mistakes to Avoid
- Do not sit in traffic with the gauge climbing and the fan off.
- Do not replace the fan motor without checking fuse, relay, and command signal.
- Do not install a larger fuse in a fan circuit.