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aux. fan help

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Is the fan running when the ac is on? See my aug 24th post and the info I got. I am still not sure that the aux fan is working off the switch as my truck never gets to the 230 mark, but replacing the ac relay on pass side fixed the running hot problem for me and fixed the ac. The relays in the system are all the same and about 10 bucks at auto parts store. I bought one and started at the radiator and exchanged it out till I found the bad one, so unless you have more than one bad relay you can run a test on system with just one. I found a wiring diagram in the dyi section under aux fan does not turn on. Good luck Ron

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mine was drivers side on the radiator, there is a fan relay that will go bad also, it is on the drivers side fenderwell


This is the aux. fan temp switch on a RENIX radiator



Some HO radiators come with the bung under a plastic plug, most don't. If it has a neck for the cap, it likely doesn't have the switch.


The temp. SWITCH runs thru the ECU and then the fan relay (on the DS fenderwell like JeffN said), the temp SENDER in the block for the gauge/light, the Coolant Temp SENSOR in the block under the manifold to ECU for fuel/air mix.

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