Radiator fan stays on when ignition is off?

ERIC PEARSON

MEMBER
2011 HYUNDAI SANTA FE
3.5L
6 CYL
AWD
AUTOMATIC
17,000 MILES

Replaced oil sensor 9 months ago, second one replaced 3 months ago. Also crank seal replaced due to oil leak. After return from the garage, the fan stayed on when ignition is switched off: small air video screen also stays on. Have only had it checked by competent non-dealer mechanic because of our location : has reset the codes from his computer terminal, but problem still exists, Also cannot lock and unlock the doors with remote control. Other than this, everything seems to work as normal, Alternator replaced last week, battery replaced a month ago. Not much support from Hyundai because we live outside the dealer network.

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like you might have an issue with the coolant temperature sensor.
It is likely sending a signal to the ECM that the engine is 'too hot' and for that reason fan stays on to 'cool' the engine.

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor
https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

The coolant temperature sensor is located on the upper part of the engine. If you are facing the engine it will on the right hand side (see diagram below).
The temperature sensor can be tested by checking the resistance value between the pins. I have attached the chart that shows the resistance value at different temperature.

Please let me know of any questions.
Thank you.

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