Radiator fans runs constantly. Turns on a few second after you start the engine. Checked the relays and they seem to be fine. Any Ideas.

Check the engine coolant sensor. Might be reading hotter then it is and that'* turning on the fan.

I replaced this sensor a while back and it did not fix the problem. Is there a way to test this? also a/c is turned off.

if you put your make model trim and year into your sig its alot easier for people to help, theres alot of different 01 buicks.

did you check the relays by switching it with a different one that you know works? usually they are ground controlled by the computer so if that wire is touching the frame any were that could be a cause too.

I did check the relays. They are working fine. I will look for a loose wire.

Thanks

thanks for updating the sig, now i can post a relevant diagram. more specifically you want to check continuity to ground on the control wire that goes to the pcm