2005 Chevy surburban fans don’t work

[Scottydoggs]

try another temp sensor, if you didnt get a delco, get one of them. all of em are subject to being dead new in the box. its sending signal to the dash, and the pcm. pcm side quits when the fans wont turn on.

if you can scan live data, scan coolant temp, see if its reading via the obd2. (aka the pcm) if its not reading right, temp sensor would be new and bad. less likely the pcm plug is dirty/corroded. rare cause its a weather tight plug. or a melted wire off its plug being its right next to the exhaust manifold.

 

[Joseph Garcia]

Yes the mechanical fan works all time. Never seen it cut off. But what I r read was Chevy did away with mechanical fan in 04 and went to electrical. I don’t thinks it’s suppose to have both fans

I would agree with you. I've never seen that 3 fan setup. I'm guessing that somebody installed the electric fans, but did not remove the mechanical fan.

 

[Marky Dissod]

No, it's not supposed to have or need 3 fans - although it's pretty cool (pardon the pun).
While the mech fan works WELL, it will most likely prevent the electrical fans from turning on, unless your engine works or plays REALLY hard, or something like that.

Take more pics. You may have the only truck with 3 fans in existence. It's definitely rare!

Make sure that the pcm is properly programmed to use the electrical fans before removing the mech fan.

 

[Scottydoggs]

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are you the original owner? thinking it got a engine swap at some point. never seen elct and clutch fan at the same time.

once you get the elct fans working right id ditch the clutch fan, you'll free up like 10 hp. and might even see a bit better mpg. less spinning mass.

 

[Doubeleive]

Yes the mechanical fan works all time. Never seen it cut off. But what I r read was Chevy did away with mechanical fan in 04 and went to electrical. I don’t thinks it’s suppose to have both fans

NOPE and the clutch fan probably isn't doing much good without a shroud but might be helping "a little", and apparently not enough (alone) if it is heating up at idle.

 

[Doubeleive]

are you the original owner? thinking it got a engine swap at some point. never seen elct and clutch fan at the same time.

once you get the elct fans working right id ditch the clutch fan, you'll free up like 10 hp. and might even see a bit better mpg. less spinning mass.

1st time I have seen one this way also, didn't think there was room for both

 

[Marky Dissod]

1st time I have seen one this way also, didn't think there was room for both.

That's why I hope he takes more pics.
But yeah, without the mech fan shroud, the mech fan will not be as effective as it could be.
Meanwhile, when the electrical fans turn on, they're just going to try to blow at the mech fan.

 

[Joseph Garcia]

One other potential issue with that setup is that the mechanical and electric fans may not spin in the same direction, which would reduce the overall cooling effectiveness.

 

[mattbta]

I have not seen this setup, either.

I _think_ 2500's (8 lug) have a mechanical fan, but never both.

If you're not the original owner, seems like maybe the previous saw the fans weren't running, either, and put a mechanical fan on it as an ineffective stopgap? From the factory, the fan parameters will put low speed on when ECT is 226*. That's pretty high. It took a while idling in Texas 100*+ heat to get my conversion to turn on even set at 205*.

Here's OEM parameters from a 2006: https://www.performancetrucks.net/f...ng-161/cooling-fan-tuning-543694/#post5356454

 

[Chevywalt66]

Taking more pics now. It never runs hot I am just trying to get my AC system right I just bought a new compressor and gonna install it. But the right electoral fan is suppose to cut on with AC but I know there is no refrigerant so it won’t come on.