How to Troubleshoot a Sunfire Radiator Fan

by Mark Robinson
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Due to the transverse layout of its engine, the Pontiac Sunfire uses an electric radiator to pass additional cooling air through the radiator, keeping the engine from overheating during extended operation and stressful loads. The engine may overheat if the radiator fan stops working, an event that can cause considerable damage to the engine if the vehicle isn’t stopped in time.

Step 1

Open the hood and locate the fuse box above the battery. Remove the fuse panel and pull out the radiator fan fuse with a fuse puller. Inspect the metal blade on the inside of the fuse if the fuse casing is transparent or use a fuse tester to verify the fuse’s operation if the fuse casing is opaque. Replace the fuse as necessary.

Step 2

Inspect the wires running from the radiator fan to the remainder of the engine’s wiring harness. Have an experienced automotive technician replace any broken, frayed or otherwise damaged wiring as soon as possible.

Step 3

Remove the radiator fan relay from the fuse block. Connect the ohmmeter leads to the positive and negative terminals on the relay and set the device on its lowest ohm range. The ohmmeter should read "Infinite resistance." If the device reads any amount of resistance, replace the radiator fan relay.

Step 4

Locate the engine coolant temperature sensor on the block of the engine. Turn the engine on and disconnect the plug leading to the sensor. If the fans fail to activate after disconnecting the plug, the radiator fan motor has failed and requires replacement.

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