Check Gages Warning Light

[winone67]

I have 2008 trailblazer LT I6 4WD. Sometimes while driving the temp gauge goes all the way to left and Check Gages Warning Lt comes on. Also, air conditioner quits functioning.

Most often the problem occures on my way to work in the morning. Vehicle sits all day and when I leave work in the evening, I drive about 2 miles and everything goes back to normal (Light off, gauge normal, and A/C functional).
Thanks in advance for any suggestions.

 

[Blckshdw]

It would be best, if you can get the DTC code read, as that will give the most direct starting point to troubleshoot. Many parts stores like Advanced Auto, or Autozone will read them for free if you happen to be near one when it happens.

The other option is to buy a cheap code reader, or get an ODBII adapter and either connect it to a laptop, or to your phone (as many of us do) and read the code yourself.

 

[AtlWrk]

Welcome

The "Check Gages" Warning Light is distinct from the check engine light (CEL) and only comes on if the oil pressure or coolant temperatures are approaching a danger zone.

If the gauge is dropping all the way to the left (cold) it is likely due to an open circuit with the engine coolant temperature (ECT) sensor. Normally, the A/C will shut off if it detects that the engine is overheating (gauge to the right) but it may also do that if it realizes it doesn't know what the engine temperature is.

Either way, the likely culprit is a failing engine coolant temperature (ECT) sensor. Plenty of threads on here about how to change it if you search.

 

[Robbabob]

I was going to type a similar reply as AtlWrk, but I had nothing for the AC not working. Probably a good assumption for the engine temp; if it doesn't know, assume it's HOT.

Good luck!

 

[Daniel644]

Welcome

The "Check Gages" Warning Light is distinct from the check engine light (CEL) and only comes on if the oil pressure or coolant temperatures are approaching a danger zone.

If the gauge is dropping all the way to the left (cold) it is likely due to an open circuit with the engine coolant temperature (ECT) sensor. Normally, the A/C will shut off if it detects that the engine is overheating (gauge to the right) but it may also do that if it realizes it doesn't know what the engine temperature is.

Either way, the likely culprit is a failing engine coolant temperature (ECT) sensor. Plenty of threads on here about how to change it if you search.

This would get my vote, but I would also add I've seen a check gauges light on my 99 firebird when my alternator died.

 

[winone67]

Welcome

The "Check Gages" Warning Light is distinct from the check engine light (CEL) and only comes on if the oil pressure or coolant temperatures are approaching a danger zone.

If the gauge is dropping all the way to the left (cold) it is likely due to an open circuit with the engine coolant temperature (ECT) sensor. Normally, the A/C will shut off if it detects that the engine is overheating (gauge to the right) but it may also do that if it realizes it doesn't know what the engine temperature is.

Either way, the likely culprit is a failing engine coolant temperature (ECT) sensor. Plenty of threads on here about how to change it if you search

Thanks. I think I can replace it once I locate it.

 

[winone67]

By the way, I put "Check Gages" because that is the way it is listed in the owner's manual.
https://www.dropbox.com/s/6ti478n70l02mdp/2015-06-17%2017.17.55.jpg?dl=0

 

[AtlWrk]

Yep, that's the one.

I was just pointing out that that Check Gages Warning Light is different than the CEL/MIL light that 99.9% of people come here for.

 

[Robbabob]

Thanks. I think I can replace it once I locate it.

Pretty sure it's behind the alternator. You have to remove the alternator to get to it. Should be in the manual as well.

 

[Mounce]

Pretty sure it's behind the alternator. You have to remove the alternator to get to it. Should be in the manual as well.

In 06 (or 05, never can remember) it got moved to the passenger side of the motor towards the back. From what I understand, it's even harder to get to than the earlier ones with it behind the alternator.

 

[winone67]

In 06 (or 05, never can remember) it got moved to the passenger side of the motor towards the back. From what I understand, it's even harder to get to than the earlier ones with it behind the alternator.

Thanks for the suggestion.

 

[Mounce]

#3 in this here grainy diagram.

-oh, and it was 06 that it moved back there so yours is also back there.

 

[Robbabob]

For some reason, I had it in my head the OP has an '05; behind the Alt. Good catch, Mounce, Saved the OP from removing the Alt and being mad at me

 

[winone67]

#3 in this here grainy diagram.

-oh, and it was 06 that it moved back there so yours is also back there.

Thanks again. That is really helpful. Any idea if antifreeze is going to pour out when I remove it?

 

[Mounce]

Thanks again. That is really helpful. Any idea if antifreeze is going to pour out when I remove it?

Maybe a little but shouldn't be a flood. Might want a catch pan in place if you're the environmentally conscious type. Just make sure the motor is cold and there's no pressure in the cooling system.

 

[Texan]

Might be a good time to change your Dex Cool (antifreeze).
Recommend every five years.

 

[gmc4flash]

So I just had to have my sons 02 envoy towed home after the check Gage's light lit ant the temp display became erratic. After it cooled off it would start with an obvious bad water pump... I'm just hoping nothing else got damaged!

 

[Eric04]

Fingers crossed. Hopefully he didn't run it too long after he noticed the problem. The old 3.8 and SB Chevys were pretty forgiving about running hot but that's not the norm.

 

[Texan]

Those old CI small blocks could tolerate more abuse
than these modern aluminum blocks.
gmc4flash, hope it just a water pump. Let us know.

 

[gmc4flash]

Well the pump froze up enough to destroy the belt...

 

[Robbabob]

You'll have that.

How long since the idler arm and pulley were replaced? For me, if it's been a long time, I'd just replace now, for the sake of it.

I was pretty scared when our pump failed, sending the temperature through the roof. All was okay once we replaced the necessary stuff.

Good luck!

 

[gmc4flash]

having a heck of a time getting shroud out, I guess I must be missing something ... pita

 

[Tiggerr]

Shroud's not coming out without taking the fan and clutch off. Not without mutilating it.

 

[gmc4flash]

so the manual says take off the bolt for the clutch, but on the end of the water pump is an electrical connector for the clutch, cant see any way to get it off.

 

[Blckshdw]

Can you post a pic of the connector?

 

[gmc4flash]

it is the connector for the fan clutch, it has a thick cable that goes out to a slot in the fan shroud where the cars wiring harness can connect to it. I was afraid to put too much force on trying to get it off the end of the fan clutch


if you have the pdf of the manual from the ftp site, it clearly shown on page 3 of the engine cooling pdf. fan is item 1 and the connector to the fan clutch is number 3.

 

[AtlWrk]

Just to be clear: you only disconnect the electrical connector where it attaches to the vehicle harness (on top of the shroud), NOT at the clutch itself. The fan, clutch and shroud all come out together.

You'll have to wrestle it all around the upper radiator hose neck, without breaking the neck or the shroud or puncturing the radiator. It's a major PITA.

 

[gmc4flash]

ok so the more I look at this... the more I realize I did everything wrong that I could do wrong, the fan clutch screws into the pump and should have been unscrewed 1st!

 

[Robbabob]

1. Unscrew large nut.
2. remove upper radiator hose.
3. remove electrical connector.
4. wrestle with the SOB until it comes out.

It's quite simple, really, once you've done a few times.

 

[gmc4flash]

yep... I now have the pump loose from the engine, the fan loose from the fan clutch and the clutch still attached to the pump... don't see how I could have made it harder on myself! I have to remount the pump to the motor so I can try and unscrew the fan clutch from the pump. Or bite the bullet and take out the radiator.

 

[Robbabob]

Oh my, yes, you did F yourself.just put a few screws into the pump. Oh, and you'll probably need to "rent" a tool from an auto parts store to keep the pump from turning while you remove that nut. It is the easiest way, unless you're lucky OR you have a hammer drill. If you've already removed your belt, chances are you'll need the rental.

I feel for you, brother.

 

[gmc4flash]

Robbabob... you are a master of understatement... I will be heading to autozone to rent the tool.

 

[gmc4flash]

wow! I will not make this mistake again... and for the record the rental water pump tools suck! I ended up bolting a 3 foot piece of square tubing to one of the 4 holes for the water pump pulley and then using the big water pump wrench to loosen it. Worked like a charm... I highly recommend it... just don't do everything else the way I did it. Thanks all for the info. (I still have to put it all back together and hope there was no engine damage...)

 

[Robbabob]

Oh man. Yeah, those tools can suck... as you did, improvise for the solution.

The great thing is..... you poses the expertise to do it now, and you will share it when you see someone struggling. Even your tool idea!

Good luck!

 

[gmc4flash]

Truck runs again... No strange noises... Hopefully that means no damage... Gonna change the oil tomorrow and then watch it to make sure it does not turn milkey... The sure site of something bad.