Radiator fans stay on after engine turned off

Tiny
RICH WHITTINGTON
  • MEMBER
  • 2010 SEAT LEON
  • 2.0L
  • TURBO
  • 2WD
  • MANUAL
  • 90,000 MILES
After finding a coolant sensor fault my radiator fans start turn straight on when I start the engine and they don't go off for 10-15 minutes after I've turned the engine off. This is still happening after replacing the old sensor, the sensor also fluctuates in temperature from 90 degrees to -40 degrees.
Wednesday, October 9th, 2019 AT 11:34 AM

1 Reply

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Hi,

You have an issue with the sensor still. Either it is the sensor itself, wiring, or the control module. The temp should obviously not fluctuate very much but the -40 is an open circuit default. Meaning when the circuit goes open it defaults to -40. This is the most likely cause of you other issues.

Unfortunately I don't have a service manual for your vehicle so I can't provide you the wiring diagrams. However, the idea would be to check resistance in the sensor wiring then check for shorts to power and ground.

Once that is okay, the control module is most likely the issue.

https://www.2carpros.com/articles/how-to-check-wiring
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Friday, October 11th, 2019 AT 1:13 PM

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