Electric Radiator Fans running more than usual

[harbison]

2009 GMC Yukon XL: I've noticed the radiator fans running when it doesn't seem like they should be. For instance, when I start it in the morning with cold engine and about 60 degrees outside. The fans seem to be operating normally, it just seems they are coming on more than they should. We've owned it since new and I've only noticed this the past few weeks.

 

[EnigmaMan]

This may be a dumb question, but do you have the Fron / Rear A/C turned on? If so its trying to pull air through the condenser to aid in cooling.
If you turn off the AC it should shut off the fans in ~10-20 seconds.

If they are always on then it could be a stuck relay - but 99% of the time when they go back they stay in the off position!

 

[harbison]

They do shut on and off. I checked the relays and switched the ones that were identical. They do run more when A/C is on, regardless of temperature. One of them sounds louder and rougher than usual. (Not sure how to describe the sound.) May need to replace fan assembly.

 

[harbison]

Update: Replaced electric fan assembly. High fan still running unusually loud and often. Not sure where to go next.

 

[TheAutumnWind]

if a/c is on (are you running the defroster?) then the fans should turn on. Thats normal.

 

[harbison]

I've owned this vehicle for eight years and driven it almost 200K miles. This isn't normal operation for this vehicle. This is a new problem that has developed over the past several months. Even with cold engine and cool outside temperatures, the high fan kicks in. The engine never overheats. Stays the same operating temp it always has. The do cycle on and off, but they are on way to much and seem like they go straight to high. The noise bothers my wife, which is the real problem.

 

[TheAutumnWind]

I've owned this vehicle for eight years and driven it almost 200K miles. This isn't normal operation for this vehicle. This is a new problem that has developed over the past several months. Even with cold engine and cool outside temperatures, the high fan kicks in. The engine never overheats. Stays the same operating temp it always has. The do cycle on and off, but they are on way to much and seem like they go straight to high. The noise bothers my wife, which is the real problem.

Ok, that does sound like an issue then. Sounds like the relay is working at least somewhat, if they still turn on and off.

I can certainly relate to the last sentence.

 

[kbuskill]

The cooling fans are controlled by the ECU... The ECU has to get a temp reading from the engine in order to know when to cycle the fans on and off and also what speed they should be running. It sounds like one the the temperature sending units/sensors is sending an unusually high temperature reading to the ECU. I would check and replace the temp sensors.

I believe there is one for the temp gauge and a separate one for the ECU but not 100% sure.

 

[harbison]

The cooling fans are controlled by the ECU... The ECU has to get a temp reading from the engine in oder to know when to cycle the fans on and off and also what speed they should be running. It sounds like one the the temperature sending units/sensors is sending an unusually high temperature reading to the ECU. I would check and replace the temp sensors.

I believe there is one for the temp gauge and a separate one for the ECU but not 100% sure.

I'll look into that. The temp gauge seems to work like it always has. I will check on separate coolant temperature sensors.

 

[harbison]

Found problem. Bad connection on Left (driver) side fan. Burned connector and prong on fan. Bad connector probably caused same problem on replacement that it did on original. Will change connector