# Testing engine cooling fan - 1.8L



## Burtess (Apr 7, 2011)

Hi there,

I am having an overheating issue with my 2011 Cruze LS with MT. Approximately 177,000Km on the car.

Dealer replaced the thermostat assembly at a cost of $500+ but the radiator fan still does not come on (PO597). The car is now giving no codes.

They ordered a different sensor and a fan assembly and suggested I could put it in myself to save labour costs.

I want to check the existing fan by running a 12V power source to it but do not know what the wires are. Attached is a pic.

The wire going into the back are as follows: left - yellow, right - black, middle upper - white/blue stripe, middle lower - grey

I assume the black is negative, yellow is positive, but don't know what the other two do.....

Can anyone help?

Burt


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## Burtess (Apr 7, 2011)

Also interesting is that even with the negative battery terminal disconnected I get a very faint beep every couple of minutes.....

Burt


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## iTz SADISTIK (Apr 6, 2014)

I'll have to take more time later to research but the other two wires should be associated with the ECU. They should have something to do with flipping the fan on and off at certain engine temps/conditions. Hope this gives you a direction for now.


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## JMcLean (Nov 4, 2018)

Yes, this is a very old question, but ...

GM went with an Extreme Relay Mess (ERM) approach with 5 separate cooling fan relays, in addition to the Engine Controls Ignition Relay.

The Yellow one is High speed fan. Grey is medium, White/Blue is low speed, if equipped. And yes, Black is ground.


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