2003 trailblazer overheating while @ idle

Fan is not cutting on.I would check for power at the fan and if you have power then i would check the coolant temperature sensor it could be faulty causing this problem.

is it overheating?? i would most likely say if it is overheating then you may have air in the system. after replacing a water pump you let alot of air into whats supposed to be a sealed air tight system. try bleeding the system real good because if there is air in it then the fan switch may not be getting a temp reading. hope it helps if not post back i got a few other ideas good luck

both fans do not turn on at the same time. one fan is for the AC condensor and the other is for the radiator. A/C turns on one fan, Radiator temp switch turns on the other one. If you have never replaced the thermostat, or done a radiator flush/refill, you should do one now.

Unplug the fan and see if it still makes noise.I think plug is on or near fan shroud, Good luck

There may be an obstruction in one of the hoses, there may be an air pocket in the system somewhere.
Are you sure there is actually an overheating going on? Maybe it's a bad temperature sensor or temperature gauge stepper motor.

Hello sneadbilly and thank you for asking your question, on Fixya.

Here is a simple process that will walk you through a few steps that will pinpoint the overheating problem on your 2003 Chevrolet TrailBlazer, without even using any tools. It has helped millions of people, and I am certain that it will help you, because I wrote it for people like you. So here is the link to:
How to diagnose your overheating 2003 Chevrolet TrailBlazer

Anyways if that helps you any little bit, then feel free to follow me on Twitter. That one is at: twitter.com/acoates23234

Thanks for the vote, and good luck!

Hello rmelton96 and thank you for asking your question, on Fixya.

Here is a simple process that will walk you through a few steps that will pinpoint the overheating problem on your 2003 Chevrolet TrailBlazer, without even using any tools. It has helped millions of people, and I am certain that it will help you, because I wrote it for people like you. So here is the link to:
How to diagnose your overheating 2003 Chevrolet TrailBlazer
You might want to pay close attention to the 'fans' section of those instructions.

Anyways if that helps you any little bit, then feel free to follow me on Twitter. That one is at: twitter.com/acoates23234

Thanks for the vote, and good luck!

The fan clutch isnt engaged at all times, therefore it may be normal to hold it in place (not recommended). On these trailblazer's 4.2L engine the fan clutch is electronically controlled. Usually when this vehicle's fan clutch malfunctions, there is a random ticking noise while idling or at a stop, also the "service engine soon" may turn on. As for the the fan speed problem, this may be a faulty blower resistor malf (typical) or climate control unit may be faulty. Hopefully this helps!!

At idle, with engine hot, is the fan blade turning?

Theory is, at idle, need the fan to pull air though the radiator, at highway speeds, the air flows through without need for the fan.

All warning lights flashing on dash of my 2002 chevy trailblazer. Runs fine all gagues go dark and turn back on every now and then. Also the gagues all go to the right or stick half way like I am idling at 5000 and going at a speed of 60mph when I am sitting still. I am thinking it has something to do with my computer because the rest of the truck is working just fine.