Overheating when idling, radiator fan not starting

Tiny
OVERHEATINGFOCUS
  • MEMBER
  • 2008 FORD FOCUS
  • 1.6L
  • 4 CYL
  • 2WD
  • MANUAL
  • 70,500 MILES
Hi
I slowed down to a crawl in motorway traffic and I had a warning light to say the engine was overheating. Pulled over to let the engine cool down and turned round to drive carefully home. I've only had the issue since by running idle for about 30 mins as the engine slowly heats up.

I understand that the radiator fan should start spinning once the coolant has reached a certain temperature but it doesn't. Nor does it spin when the A/C is turned on.

I've bypassed the fan control module and run the 12v straight into the fan and it spun up so I've determined that nothing is wrong with the 12v fan fuse or fan itself. I got a replacement control module from a breakers yard but it doesn't make a difference. Granted the replacement could be broken also.

Now I'm looking at the smaller diameter cable which ultimately joins the 12v lines going into the control module from the thermometer and other triggers. I'm guessing that if there is an issue with the thermometer that turning on the A/C would still start the fan at a slow speed? Neither start the fan so could it be a relay I've read about? I'm struggling to find the relay, doesn't appear to be in the fuse box close to the battery.
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Thursday, July 8th, 2021 AT 12:48 PM

5 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good afternoon,

I attached a diagram for you for the fans. I would check the fuses listed for power on both sides.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-check-a-car-fuse

I also attached the location of the relays for you. They are in the underhood fuse block.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

You will need to do some voltage checks to determine the failure.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Let me know the results so we can continue with the testing.

Roy
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Thursday, July 8th, 2021 AT 1:53 PM
Tiny
OVERHEATINGFOCUS
  • MEMBER
Hi there,

Before we go any further I've attached pictures of my junction box which looks quite different to the ones linked above.
Thanks for your help. :)
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Sunday, July 11th, 2021 AT 11:08 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, can I have the complete VIN number of the car?

Roy
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Monday, July 12th, 2021 AT 1:40 AM
Tiny
OVERHEATINGFOCUS
  • MEMBER
Sure:
WF0PXXGCDP8K34508
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Monday, July 12th, 2021 AT 8:15 AM
Tiny
ASEMASTER6371
  • EXPERT
Thank you.

Let me get the cross over for you.

Roy
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Monday, July 12th, 2021 AT 9:42 AM

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