Fan always runs when the engine is running

[boomboom]

I have a 2000 SL2 and the Radiator fan always runs when the engine is running. The temp guage is always just above the 1/4 mark. I replaced the cooling fan relay, but did not fix the problem. Any ideas why the fan is always running? It goes off when I turn off the engine.

Thanks.

[boomboom]

Found that the fan runs all the time when the heater is set to defrost. This is by design. Not sure why.

[magnetman]

When the comfort control knob is set to defrost and the temp is above, I believe 42 or 45 the fan will run all the time, this is normal.

However it does sound as if you might have a bad ECTS (engine coolant temp sensor) or a stuck open thermostat. The temp gauge should read about 3/8 to 1/2 most of the time. If you have an older ECTS this could give false readings. On the upper drivers side of the engine, just below the EGR valve, back behind the air intake, is where you'll see the ECTS. Here's a photo of the old version and the new version. Note the shoulder on the new version.



The old ones can crack and give false readings. Check for the shoulder on the ECTS. If it looks like the new then chances are you have a stuck open thermostat. If it's the old version, change it out and see what reading you get. Here's a how to on the Satrunfans.com site. Become a member it's worth while!!

http://www.saturnfans.com/forums/showthread.php?t=24003

Also check and see if the connector on the ECTS is corroded. This could send a bad reading as well.

Hope this helps some.

[ronaldk]

When your air cond compressor is on your fan is on.

[magnetman]

Originally Posted by ronaldk

When your air cond compressor is on your fan is on.

If the temp is above 45 or so!!

[ronaldk]

It has nothing to do with temp. If you shut your air conditioner off and your veh is cold and the fan runs you have a problem, if fan stays off but when you put air back on the fan runs thats normal. The fans will come on without air being on should eng start to get hot. But hot or not if you turn on air conditioner the fan is meant to come on.

[magnetman]

Originally Posted by ronaldk

It has nothing to do with temp. If you shut your air conditioner off and your veh is cold and the fan runs you have a problem, if fan stays off but when you put air back on the fan runs thats normal. The fans will come on without air being on should eng start to get hot. But hot or not if you turn on air conditioner the fan is meant to come on.

Original poster said, "Found that the fan runs all the time when the heater is set to defrost."

I said that it will run if the heater is set on defrost if the outside temperature is above a given threshold... ie 42 or so degrees. In this case the outside temp does make a difference. Maybe I should have said "outside" temp..

[ronaldk]

He has a problem as you pointed out (magnetman) with his ects. He says his temp gauge reads 25% at all times,so he needs to change. But as far as the coolent fan,it is a fact that the air conditioner compressors relay is connected to the fan relay and if the air is turned on and the system is funtioning the compressor relay will engage the coolent fan relay turning on his fan. I am trying to answer him as to why he thinks fan is always on. If he shuts his air he should see fan shut as long as the brain is not tricked by ects.He needs to change that ects but I just wanted to get a reply from him as to fan on or off with air off so we both had a better understanding of him having or not having a real problem.Trying to help people long distance you need as much info as they can supply.

[RC1488]

More info is needed.

Exactly when (as in what is on/off) does the fan turn on.

If the temp gauge reads 3/8's the ECTS is suggested to be good. However it is advised to replace it as preventative maintenance regardless.