Fan won't turn on

[progress1vebmx]

Just flushed radiator etc etc.

Tonight, 65 degree day. After driving for a little bit I get to a stop light. My temperature goes up to 170 degrees and I hear my fans turn on, my temperature immediately drops to 160. I get on the highway, my temperature rises to about 190 degrees and doesn't go down. I don't hear fans or anything. 5-7 minutes later, I get to a stop light and my car is still running at 190 degrees. I get home, still running at 190. No fan. I turn the ignition on, fan doesn't turn on.

Any ideas?

The previous owner install some fan switch... there is a switch that makes it computer controller, or manual control, and a button that turns it on and off if it's manually controlled. Doesn't seem to work.

 

[MeanBuicks]

The factory fan controls are pretty involved. You have a signal from the ecm (that depends on the coolant temp sensor), a low speed relay, high speed relay and a delay relay. Power to the fan system comes from a connection at the starter through a fusible link.

Make sure you have power to the relays first. Run a jumper to the fan connector to be sure the fan motor is good. If those check out good, start investigating the relays, etc.