Go back to previous topic
Forum namePerformance/Engine
Topic subjectWhen are rad fans suppose to come on?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=114955
114955, When are rad fans suppose to come on?
Posted by jay777, Jul-27-08 07:25 AM
I've read a lot of things that contradict one another so I just want to get this all cleared up so I can try and diagnose the problem I'm having.

I know the rad fans are suppose to come on at operating temperatures but is that only the case while your driving? Will it come on while in idle?

The reason I want to clear this up is because I swapped out my stock rad and fans for a new one that just has a single fan. It's hooked up to the driver's side harness, but it won't come on when operating temps are reached at idle. The only time it turned on was when I turned my A/C on.

What should I do?

Thanks guys
114956, RE: When are rad fans suppose to come on?
Posted by shybuck, Jul-27-08 07:31 AM
You should plug into the other connector, We have to fans, 1 for rad/block cooling and 1 for a/c. The block/rad fan will come on if idling at when the temp sensor reads 210 degrees, I believe. The other only runs with a/c.
114957, RE: When are rad fans suppose to come on?
Posted by jay777, Jul-27-08 08:42 AM
But when I plugged the fan into the driver side and passenger side (at different times), the fan worked when I turned on the A/C, so both harnesses are connected to A/C?? I'm lost.
114958, RE: When are rad fans suppose to come on?
Posted by Nightfall, Jul-27-08 11:33 AM
Yes, both fans will come on whenever you turn on the a/c regardless of engine temp. Only the one without a/c when it gets hot.
114959, RE: When are rad fans suppose to come on?
Posted by Star Turbo Talon, Jul-27-08 03:50 PM
The drivers fan has a high speed fan and a low speed fan. Make sure your not hooked up to the high speed fan. The high speed fan might only come on when the a/c is on and below a certain temp.

The fan should come on after 200~210 degrees at idle. I think mine comes on at 200.
114960, RE: When are rad fans suppose to come on?
Posted by jay777, Jul-28-08 11:52 AM
Originally posted by Star Turbo Talon
The drivers fan has a high speed fan and a low speed fan. Make sure your not hooked up to the high speed fan. The high speed fan might only come on when the a/c is on and below a certain temp. The fan should come on after 200~210 degrees at idle. I think mine comes on at 200.


Ok, I have it hooked up to all four wires.

-Blue with white stripe & black with white stripe connected to the positive wire from the fan
-Black wire and black wire connected to the black ground wire from the fan.

The fan only comes on when the A/C is turned on. I let it reach operating temps and nothing came on. The thermostat opened and coolant started flowing through the radiator to be cooled, but the fan didn't come on.

Am I missing something here??

Thanks for the help thus far guys.