Hey everybody, hope everyone is well. Quick question for everybody. I drive a 2002 v6. Today, I noticed that the fan was staying on all the time then later on I realized that the temperature gauge wasn't working either. Does anybody have any ideas? As a volvo tech, I'm inclined to say that it is the coolant temperature sensor that has failed. Has anybody had the same situation occur? Also, where is the CTS located on the 3.8 engine? Is it the sensor right above the water pump with the three wires coming out of it? I have alldata (nodata) at work, but I just want to get a head start on it before I head to work tomorrow to check it out. Any ideas or directions that will help will be greatly appreciated! Thanks everyone!

 

It's so funny that you posted this. I'm having the same exact problem with a 2001 Firebird V6 I got a couple of months ago. The fans come on as soon as I start the car (and it's freezing here), and stay on, and my temp gauge never moves at all. I thought it may be the cts too, but mine seems to be one of the relays for the fans. There are 3 of them under the hood in the box. When I took them out, tapped on them a couple of times, and put them back in, the fans went off, and the temp gauge worked normally. So that makes me think it's a realy, and not the cts, or the fans would still come on when the relays were put back in. I'm gonna replace all 3 relays, since I honestly cant tell which one is bad (if anyone knows how to test them, please let me know). I had the same problem when I first got it, I changed the t-stat and it worked fine after that until last week. I only drive it maybe once a week tho. So the sticking relay was probably my problem to start with, it just unstuck when I was messing with everything to change the t-stat. But try that first, starting the car, and when the fans come on (and if yours is like mine, they blow REALLY hard..lol) take all 3 relays out, tap them and put them back in, and see if the fans come back on. That may be your problem.

 

Lol, that's funny. They blow at 100 percent; max power all the time. It just got really, really cold in California with all the storms and what not. Perhaps the cold through one of the relays over the edge. Ill figure out how to test them tomorrow with the help of a master tech and get back to you. Does anybody else have any ideas?

 

The gauge and the pcm use diffrent temp sensors, so the problems do not seem to be related.
If the check engine lite is lit. it may be the reason the fans are always on, or there is a problem with the ECT sensor or its wiring, or a problem with the circuitry from the PCM to the fans.
The gage has its own sender, and it could be a problem with the sender, wiring, or gage.
The thermostat should keep the engine warm regardless of what the fans or gage are doing.

 

No check engine light on yet..however, I'm scared that I will overheat so I've been having the heater on full blast. That being said, the master tech is going to smog my car tomorrow. I realize that since the check engine light is not on, there won't be a problem with that area of the test. However, does this mean that the engine has gone into limp-home and has started to run rich since the pcm may not be getting a signal?

 

My check engine light did eventually come on.....PO128, coolant temp below thermostat regulating temp. The coolant temp can be low for several different reasons, and in this case it was the fans blowing on high constantly in 32 degree weather. And these fans on the V6's blow a LOT harder then the ones on my Z28 do. I can barely hear the z's fans when they are running, even with the hood up and my head right at them. I have to stick my hand in front of them to feel they are blowing. But the V6 fans blow like on high speed, and I mean high. You can hear them running from inside the car, doors and hood closed. Open the hood and you know they're running, they're louder then the engine. I understand that the gauge and the pcm use different sensors, but when the fans went off, the guage then warmed up normally, and the check engine light went out. Now whether the fans are staying on because of the relays, the cts, or some other reason doesn't matter. When the fans stopped running all the time, everything was normal. So I think they are related.

 

well, I'm going to go screw with the relays here in a bit and see what's going..it's weird that I heard the fans running and then noticed the gauge not working.

 

That's the easiest thing to do. Pull the relays, the fans will stop working. Then just let the car sit running long enough to warm up to see if the temp gauge works normally with no fans blowing, then you'll know that's your problem. If your car is like mine, it will take a few minutes if you start it cold for it to warm up, then your gauge will start moving up all of a sudden and get to where it should be pretty fast. I'm anxious to see if yours does like mine...lol

 

Okay, so I pulled the relays one at a time and obviously the fans cut out one at a time. Okay...that didn't do anything. I pulled the 40 amp fan control fuse and messed with that for awhile. Then I decided to pull the 10 amp fan control and leave the 40 amp control and the three relays in place. Took the car for a drive and nothing...all of a sudden the gauge read right smack in the middle. Came back to work, fans were off. On during defrost and a/c on low setting. On and off when they should be. Lol, interesting.

 

Let me see if I understand....you pulled the 10 amp fuse, left it out, and the fans are working as they should?