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2008 chevy trailblazer_ls
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Discussion Starter · #1 ·
I have a 2008 Trailblazer I6 2WD with 146,000km/91,000 miles in Saudi Arabia.

1. The first and foremost issue is the temp gauge not moving. I first thought it was the thermostat, but when I removed the battery cable and hooked it back up, it worked fine for about 15 minutes of driving, then fell again. This leads me to believe its the ECT and not the thermostat. Am I correct? I also read the A/C won't turn on if the temp gauge is not working properly. This seems to be the case.

2. Before This happened, when I use the heat(yes it gets cold in the mornings here in December), the right side blows cold and the left hot. I had the codes read and it stated the A/C control module had an error. I guess I have to replace the entire thing.

3. My other issue is the Stabilitrak randomly not working. Some days nothing and other days the repair light comes on.

4. Lastly, the low air tire light comes on even when the tires are full. Not that big of a deal, I don't think.

Maybe the dust of from the dessert result in some of these failures.

Since I'm in Riyadh, I can't fix much of anything myself with no tools or garage and the mechanics here are an all day adventure. I'm just trying to arm myself with knowledge.

Thank you for your time.
 

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2004 gmc envoy_slt
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Does the temp gauge drop to the 100 deg. mark or does it go off scale? If it goes off scale, it is the stepper motor in the cluster. If it goes to the 100 mark, it is either the ECT or a poor connection at the ECT.

As far as your HVAC problem, I would suspect a bad temperature actuator before condemning the control unit.
 

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Discussion Starter · #3 ·
Thank you,

It sits at the 100 mark. It doesn't drop off scale. I also suspect poor gas mileage.

I don't think I can check the connection without tools, but I'll give it a go in the morning.
 

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2008 chevy trailblazer_ls
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Discussion Starter · #4 ·
So its currently at the mechanic. I picked up the sensor and had to show him where it was. He thought it was behind the alternator like the earlier models.

He said he has to drop the exhaust manifold to get to it, so its an all day project. I thought if he had the proper tools he should be able to get to it without moving the manifold, but I let him do it anyway.

Will update later.
 

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I think the mechanic is wrong, the ECT is located at the very back of the block, but from diagrams I have seen, it is above the manifold. Is he trying to make this a more expensive repair?
 

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2006 chevy trailblazer_ls
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672 Posts
I think the mechanic is wrong, the ECT is located at the very back of the block, but from diagrams I have seen, it is above the manifold. Is he trying to make this a more expensive repair?
Sounds like a more qualified mechanic is needed here.
 

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Discussion Starter · #7 ·
So I tried to reach the sensor myself with a wrench in his garage. I couldn't get to it, but thought an angle socket or something could get it. He didn't have one. Welcome to Saudi Arabia, there are no "qualified" mechanics. Just expats who bought a lift and a tool set.

So, the exhaust manifold was taken off. It had a small crack on it. They welded it.

When I picked it up, everything was fine. Temp gauge was working, no check engine light. 10 minutes after driving the brake peddle goes soft and I can only stop when it hits the floor. This was at first intermittent, then constant.

I take it back to him. He is confused and saying he only worked on the passenger side of the engine, opposite of the master cylinder. He bleeds the brakes, that didn't work. So I had to go and buy a master cylinder and fluid. I don't know how much he is going to charge me for the install, but it should be free. His Saudi sponsor may not allow that.... I'll pick it up today.

I miss my garage...
 

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Discussion Starter · #8 ·
Just picked it up. The brakes worked better than ever. New master cylinder. I gave him half of what he asked for which came out to 25 bucks.

After 10 min of driving the thermostat went back down to 40C/100F.....the same effect as when I unhooked and re-hooked the battery.

The cable that runs from the ECT sits on the engine. I don't know if that could have anything to do with it. The desert dust, the heat? Could it be the actual thermostat if the temp gauge is normal after resetting the battery? What else can I have checked? I know I need to find a proper electrician.

I'm more concerned that the A/C doesn't work if the temp gauge is not working. We just have another month of cool weather. Is there a bypass?

Thank you again.
 

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Discussion Starter · #9 ·
it was the thermostat. The sensor was a waste of time, but at least i know its not that.

A/C and temp gauge are working great.

Still trying to figure out the stabilirak connection codes. U0101 U0073
 

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2004 chevy trailblazer_lt
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Engine Temp gauge and A/C

I have a similar issue with my wife's 08 TB.

Temp gauge sits at 100. No A/C.

Reset the electrics [disconnected battery] for 10 minutes. Temp gauge and A/C worked fine for the next drive [15 minutes]. Then when next start-up, temp gauge back to 100, no A/C

Manual climate controls, so it seems there would be no outside air temp sensor to go bad.

Hooked up an OBDII reader and it shows the engine temp sensor functioning properly [engine temp slowly increases and then stays at 175 when warmed up] So I guess the temp sensor is working, and the thermostat is working.

However, the engine temp gauge on the instrument panel is stuck at 100, and no A/C.

Any thoughts?
 

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2008 chevy trailblazer_ls
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I'm fighting the same ghost on my wife's 08 trailblazer. changed the temp sensor, for anyone trying this it's on the L6 its behind #6 exhaust and I cut a slot in a 15mm socket for the wire to fit. just have to take the heat shield off for some room. Ended up a waste of time. I'm debating between PCM or harness issue. I got the AutoEnginuity scanner software and GM extension and noticed even getting reading that sensors are not acting quite right. then one by one they come back and the even the scanner program lays out different. occasional I get the engine temp threshold code which is right but the gauge should not read 100. Unfortunately for me we are in the heat of the summer and my wife knows about the disconnect the battery trick. so by time I get home to hook up the laptop all is right. may have to teach her how to use the software and have her record it. My 04 Colorado had a bad thermostat for years and the only problem I had was poor heat in the winter.

I was an ASC mechanic years ago but this vehicle is before my time. I will keep you posted how it comes out of if I just run it off a cliff.
 
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