Fans don't work
Where is temp swich
on90 Buick regal 3.1
The ECM controls the fans, if you are lucky it could be as simple as a relay. I would start by checking both fans...at the plug jump 12v and verify that the fans work. Then find the relay box (probably under the hood) and there should be a layout of the relays on the underside of the cover. By switching relays, you can find the bad one....... I am attaching the fan schematic from 1990 Reatta/Riviera and yours should be similar. The ECM turns on different relays starting with the one on the engine side of the radiator, then when you turn on the A/C the one in front of the radiator turns on...at this time both are running at 1/2 speed...if the water temp goes over the preset (about 230), both fans go to full speed until the coolant temp drops.
