GTD fan sensor

[Paul Williams]

Hi guys my new years resolution is to drive me car more so want to get a few jobs done
My fans don't seem to want to come on when the engine reaches a temperature I have to switch manually can someone tell me what I need to check to get them working
Cheers Paul

 

[DaveC]

Looks like you are running a basic temperature switch sitting right there on your radiator end tank. This is either grounded or +12v depending on how they wired it. When the coolant temperature gets to the rated temperature of the switch, the switch closes to complete the circuit. This completed circuit then runs to your cooling fan relay pin 85 or 86 to energize the solenoid in the relay to send high amperage +12v your fans.
I'd start by swapping out the relay, that would be an easy fix.
You can check your temp switch by testing for continuity across its pins at ambient and hot coolant temperatures. You should have a closed circuit at 180F+ or whatever the switch is rated for.
Where in the circuit are you manually turning on the fans?

 

[DaveC]

I'm assuming that you have a manual cooling fan toggle on your dash, this would be spliced between your temp switch on your radiator and the cooling fan relay to energize the relay. So your relay is likely good. Your coolant temp switch likely needs replaced.

 

[Paul Williams]

Looks like you are running a basic temperature switch sitting right there on your radiator end tank. This is either grounded or +12v depending on how they wired it. When the coolant temperature gets to the rated temperature of the switch, the switch closes to complete the circuit. This completed circuit then runs to your cooling fan relay pin 85 or 86 to energize the solenoid in the relay to send high amperage +12v your fans.
I'd start by swapping out the relay, that would be an easy fix.
You can check your temp switch by testing for continuity across its pins at ambient and hot coolant temperatures. You should have a closed circuit at 180F+ or whatever the switch is rated for.
Where in the circuit are you manually turning on the fans?

Cheers dave