Thread: Cooling System/Sensor Acting Weird, A Puzzle for Experts

Your low speed fan comes on at 217 and the high speed is 226 since you have an 04+ car.

There are 3 relays for the fans. The fans are wired in series for low speed, that's how they get the low speed out of them.

The fans are wired in parallel for high speed operation, and this is the reason there are 3 relays, 2 are for high speed and 1 is for low speed.

DHP must give you guys different numbers than HPT.

Because every 2004+ file I have says 219 and 228.

I'll look when I get home.

i cant speak for a impalas fan settings, but the gp's are set pretty high, like 217 ish then they come on.

That's about right, but you aren't really going to see when the fans actually come on depending on conditions. It takes time to cool once they do come on so the temp will rise 2-3* before it starts to drop.

I'm still over here trying to figure out why fan 2 never gets to high speed . That's my issue at least.

You have all 3 relays right?

Gentlemen, after a long online research and calling experts, I found a very interesting website with a few articles about this thread that I started, I hope it helps many of us. The sensor does not last forever. Here are two samples:

http://www.underhoodservice.com/diag...ature-sensors/

http://www.underhoodservice.com/satu...rature-sensor/

Thanks to everyone who read and/or replied here.

It looks like I will have to ignore the warning that I received here about changing or messing with the sensor, since I already bought a new AC Delco (made in Israel) one.

And, BTW, I mentioned something wrong above, when I said that the voltage coming to the sensor was 1.2V. I measured the voltage between the two wires coming to the sensor when it was unplugged and that was wrong. I just measured each of the wires with respect to battery ground and they were 0 and 5 volts.