Cooling fans not turning on?

2006 VOLKSWAGEN JETTA
205,270 MILES • 2.5L • 5 CYL • 2WD • AUTOMATIC
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CMARLEY
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I changed the water pump, radiator, cooling fans, thermostat, temperature sensors, and heater blower. Checked fuses, none blown. Please help.
Mar 28, 2025 at 1:54 PM
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STRAILER
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Do the fans come on when the A/C is switched on? We can tell if the fan has a bad ground by checking the power when the AC system is on. Please test the red wire, also, see if there is power to the fuse #3 in the fuse panel under the hood. Also, check the ground which is the brown wire, this guide will show you how:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

The ground G642 is at the left side of the engine compartment. Make sure to disconnect the fans before testing. Let me know what you find.
Mar 29, 2025 at 11:25 AM
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CMARLEY
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I apologize for needing clarification. Test the fans when the A/C is running? If they don't come on, unplug them and then test
the red wire on the fans, correct?
Then test fuse # 3 under the hood and the ground.
Report back to you.

Mar 29, 2025 at 4:05 PM
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STRAILER
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Yes, start the engine and turn the A/C on to see if the fans are coming on. If not check fuse #3 and if that is okay see if there is power to the red wire and if so, check the ground and it's okay the fan motor module is bad.
Mar 31, 2025 at 11:06 AM
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CMARLEY
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Fans didn't come on when turned on AC. Changed out fuse 3 then they came on. Was driving when I lost AC, Heat & Fans. Switched out relay
and they came back on. But still boiling out of overflow tank.
In the wire diagrams I have seen, it usually shows (2) 100 (white) relays. But my car had a 100 (white) relay & a 465 (gray) relay. So when I said switched out relay, I switched their positions.
Do I need 2 - 100(white) relays?

Apr 1, 2025 at 11:46 AM
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STRAILER
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So the fans are working while the engine is overheating? If so, the cooling fans are not the problem, you may have a stuck thermostat, or the engine has a blown head gasket. Please go over these two guides to help confirm the issues:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://www.2carpros.com/articles/head-gasket-blown-test

Please go over these guides and get back to us.
Apr 2, 2025 at 10:44 AM