buffboyali

Hello everyone. When I start the car the fan won't kick on unless I turn the AC on. The radiator boils after about 10 min with the fan off and car in idle. There is no coolant boiling out from under the cap. The upper part of my radiator is boiling. My car is 05 v6. Thanks.

wayne613

Can ya plug it in to an ODB-II reader somewhere, say autozone? See what the thermostat is reading? My guess would be the thermostat is kaput since the fan "works". Just not being kicked on.

Nuke

Here's the wiring info for the fan: http://iihs.net/fsm/?dir=40&viewfile=Cooling Fan.pdf

Any chance that you have a custom tune and the fan settings have been changed in the PCM?

wayne613

Yeah, I'd check those 2 fuses first, unsure if the A/C uses either of those. F40(15A fuse) and F3(40A fuse), both in BEC.

buffboyali

I dont have a custom tune. So far some people have said it can be the engine coolant temperature (ECT) sensor that needs to be replaced or the fan relays. I dont know what I should begin with checking.

AzPete

I would guess the relays are working since the fans work with the A/C. Check the ECT first.