Fans not kicking on unless I turn the AC on.
Asked by GuruC3JMY Mar 16, 2019 at 01:19 AM about the 2007 Pontiac Grand Prix Base
Question type: Maintenance & Repair
Temperature gauge goes a little over halfway
point when idling. I know the fan motors
work since they come on when AC is turned
on. How do I figure out what’s causing the
fans not to kick on when they’re suppose to?
3 Answers
Might be a bad engine coolant temp sensor, which would tell the ECU to turn the fan(s) on when engine has reached a certain temp. Some vehicles might also have a separate fan control module for the fans. Check both, and fuses/relays too.
How do you check the temp sensors, fuses, and relays I have no check engine light on?
Fuses: pull and visually inspect (or buy a simple tester). Relays: swap with a similar rated relay, or test with a multimeter. ECT: Google how to test them, can be done with a multimeter or voltmeter. Autozones web site has a repair guide for testing coolant temp sensors for most car models, although you'll have to join to see it.
