Found this on a Blazer forum: As an Electrical Engineer who now owns an auto shop I can say I saw the design flaw fairly quickly with these 3.6L engines (Blazer came into the shop with P0128, AC not working, Steering Assist Reduced, and Temp Gauge not working). Luckily there is a fairly easy solution I will detail below after gory details of issue. You can separate the Coolant temp sensor wires from the wire harness and move them a little (OK easy meaning no knowledge or special tools or hours of work). First the problem is the ECT is a two wire (signal + and -) 26 gauge wire running through the ignition coil wire harness. Ignition coil signals are very high voltage and fairly fast frequency which causes a lot of EMI which is easily picked up on a 2 wire voltage based wire set. The ECT wiring should have been a twisted shielded pair if running next to Coil wiring or they could have used a single wire resistance thermistor, but they should have just routed the signal a different way to begin with. This is a design issue and it should be a recall...maybe a class action lawsuit is needed to force them to fix it correctly. The FSB (field service bulletin) fix blames loose connector terminals and it patches the computer software to not include ECT wire failures in the Steering, AC, and temp gauge inhibit logic (overtemp readings will still fail off these functions). Also the P0128 code can come back occasionally. Now back to the fix. Find the ECT under the air inlet and follow the sensor wire about 10-12 inches back from the sensor. You will find another connector in line for the ECT, disconnect it there. Now you can work with that connector (don't pull too hard or you may break wires), pop up the body clip holding it down and follow it forward to where it joins the harness right at the turn to the back of the engine. Here take a nice new razor blade (the hook curved ones are less likely to cut a wire) and cut thru one layer of the cloth friction tape to make an end to unwrap the tape. Use good pliers to pull with if you need to. Unravel tape until between the 1st and 2nd coil, you will have to cut a couple of tie-wrap body clips and you may need to cut the tape again. I was able to do it in about 15 minutes. I advise taking a break or two if you get tired as it can be a difficult position and it is better to take your time and not cut wires you have to fix later. Once you have those two wires (light blue and black) separated from the mass of other wires, wrap the wire bundle again with some friction tape and tape it back to the cut tie-wrap body clips. I put the ECT wires into some small split loom and brought it over the engine to the fuel rail that passes next to the ECT sensor. Then plugged the connector back to the sensor side. I tie wrapped the rerouted ECT wire to the fuel rail. Clear the engine codes and drive a happy car again.
@@thebull-des14698 I haven't actually performed this repair yet. Both of my daughters drive Blazers and have had the code thrown a couple of times and took it to the dealer since their vehicles were in warranty still. If it happens again out of warranty I give this a try. I'm also an EE and this fix, that I copied from a Blazer forum, made sense to me.
Thank you for the information. How far up through the wire harness beyond the tail end of the ECT wire connector does the ECT wire have to be stripped out? you make mention to the first or second coil. Which ones are the first and second coil? Where does the feed for ECT actually feed from? Any pics or video would be helpful. Thanks
@@adammilenkovski5809 Would this be covered under my 60k warranty. I keep having same issue as soon as i moved to a place where the weather is colder and every time it drops below 70 degrees outside it goes to cold and the power steering assist comes on. My heat still works but not the AC. Please help feeling frustarted
Just replaced the thermostat in a 2017 XT5 with about 45000 miles on it. Outside of warranty and cost just under $1300 plus tax so about $1400. These are not easy to change. I hope it works for a long time!
This happens to me but no code or check engine light, I just hear the fan blow on real loud and the temp gauge doesn’t work. Was going to get a sensor from auto parts store to change it, did that work for you?
The same thing happened with my 2020 Blazer it has 67k miles I’m a single parent what would you suggest to do I’m so tired of mechanics getting over on me. Will you suggest?
There is a TSB on how the ECM (Computer) needs to get an update at the dealership. If not with warranty, you may have to pay, but it will more than likely be the cause over replacing something that doesn’t need to be fixed. TSB # 22-NA-054
2019 blazer, bought used with 49000+/-miles, 2 days later shudder in shifting, goes to dealership they replace valve body and torque converter. 5 days later go visit son at college 700 miles round trip. Next day PO128 shows up steering assist disabled which leads to this thermostat/ sensor issue. Still got warranty but one service guy says drive it in - I said I’m 50 miles away if thermostat is stuck that won’t be good. Next day we call dealership and set up a tow that will fall under warranty…. Hope this doesn’t have to get uglyOnly 50000 miles . INSANE GM like this guy said DO YOUR PART,
We did , but I got called to work and the wife had to take to dealership and sit and wait. Will get the invoice and info for you in a day or two. So far so good. Sorry for the delay.
So we ended up taking the vehicle in the GM, after they told us the Thermostat was bad I argued the fact that I just put a brand new one in 3 months ago, GM agreed to pay for the replacement, the Thermostat still looked brand new, it was covered under warranty and has another 2k warranty on it. If your is doing this fight it, even if its over 60K, this is a known problem and GM knows it, otherwise it will cost you around 1k to have it fixed. I should of fought the first one, Im pretty sure they would of covered that one too.
Today 10.5.23 Problem still not fixed, ECM flashed, new thermostat ( well another new one) and they are still not sure, going to change out the temperature sensor, the same one I changed out a few months ago then when that doesn't fix it they are going to replace the ECM, not good...very frustrated but they are covering it all so far.
@boxstudio1506 So, this round they changed out the temp sensor, drove the vehicle for several 30 minutes trips and the code hasn't returned yet, we'll see.
@boxstudio1506 10.11.23 GM replaced the temp sensor I just installed a few months ago and so far the code has not returned, the temp sensor cost 10 bucks....it's cheaply made.
Hi James, can we speak via email or text the same problem just happened to my wife’s blazer and want to know the best way to handl this situation with gm or myself. Thanks let me know?
You all wasting money. The ect sensor is in a harness with 26 gauge next to it high voltage which will cause interference. Thats the design flaw not the thermostat or sen sor. Down the road it will happen again. If u do not take out the ect wiring from the high voltage harness. I found this out from a electrical engineer.
Thank you for the information. How far up through the wire harness beyond the tail end of the ECT wire connector does the ECT wire have to be stripped out? jeffberan6794 mentions to the first or second coil. Which ones are the first and second coil? Where does the feed for ECT actually feed from?
Found this on a Blazer forum: As an Electrical Engineer who now owns an auto shop I can say I saw the design flaw fairly quickly with these 3.6L engines (Blazer came into the shop with P0128, AC not working, Steering Assist Reduced, and Temp Gauge not working). Luckily there is a fairly easy solution I will detail below after gory details of issue. You can separate the Coolant temp sensor wires from the wire harness and move them a little (OK easy meaning no knowledge or special tools or hours of work).
First the problem is the ECT is a two wire (signal + and -) 26 gauge wire running through the ignition coil wire harness. Ignition coil signals are very high voltage and fairly fast frequency which causes a lot of EMI which is easily picked up on a 2 wire voltage based wire set. The ECT wiring should have been a twisted shielded pair if running next to Coil wiring or they could have used a single wire resistance thermistor, but they should have just routed the signal a different way to begin with. This is a design issue and it should be a recall...maybe a class action lawsuit is needed to force them to fix it correctly. The FSB (field service bulletin) fix blames loose connector terminals and it patches the computer software to not include ECT wire failures in the Steering, AC, and temp gauge inhibit logic (overtemp readings will still fail off these functions). Also the P0128 code can come back occasionally.
Now back to the fix. Find the ECT under the air inlet and follow the sensor wire about 10-12 inches back from the sensor. You will find another connector in line for the ECT, disconnect it there. Now you can work with that connector (don't pull too hard or you may break wires), pop up the body clip holding it down and follow it forward to where it joins the harness right at the turn to the back of the engine. Here take a nice new razor blade (the hook curved ones are less likely to cut a wire) and cut thru one layer of the cloth friction tape to make an end to unwrap the tape. Use good pliers to pull with if you need to. Unravel tape until between the 1st and 2nd coil, you will have to cut a couple of tie-wrap body clips and you may need to cut the tape again. I was able to do it in about 15 minutes. I advise taking a break or two if you get tired as it can be a difficult position and it is better to take your time and not cut wires you have to fix later. Once you have those two wires (light blue and black) separated from the mass of other wires, wrap the wire bundle again with some friction tape and tape it back to the cut tie-wrap body clips. I put the ECT wires into some small split loom and brought it over the engine to the fuel rail that passes next to the ECT sensor. Then plugged the connector back to the sensor side. I tie wrapped the rerouted ECT wire to the fuel rail. Clear the engine codes and drive a happy car again.
Thank you for this my bf is having the same issue with his 2020 blazer
Appreciate the help, but by chance could you share a video of where the sensor is and how you fixed the wires?
@@thebull-des14698 I haven't actually performed this repair yet. Both of my daughters drive Blazers and have had the code thrown a couple of times and took it to the dealer since their vehicles were in warranty still. If it happens again out of warranty I give this a try. I'm also an EE and this fix, that I copied from a Blazer forum, made sense to me.
Thank you for the information. How far up through the wire harness beyond the tail end of the ECT wire connector does the ECT wire have to be stripped out? you make mention to the first or second coil. Which ones are the first and second coil? Where does the feed for ECT actually feed from? Any pics or video would be helpful. Thanks
I need to know what happened in on the same journey
We all need to start a class action law suit against Chevy...How else are we gonna get this solved? They need a recall asap !
It's a wiring issue not thermostat or sensor. fixed mine with out spending a dollar. Gm thinks it's thermostat but it's not. And is not the sensor.
@@adammilenkovski5809
Would this be covered under my 60k warranty. I keep having same issue as soon as i moved to a place where the weather is colder and every time it drops below 70 degrees outside it goes to cold and the power steering assist comes on. My heat still works but not the AC. Please help feeling frustarted
Just replaced the thermostat in a 2017 XT5 with about 45000 miles on it. Outside of warranty and cost just under $1300 plus tax so about $1400. These are not easy to change. I hope it works for a long time!
👍🏼
This happens to me but no code or check engine light, I just hear the fan blow on real loud and the temp gauge doesn’t work. Was going to get a sensor from auto parts store to change it, did that work for you?
Yes
The same thing happened with my 2020 Blazer it has 67k miles I’m a single parent what would you suggest to do I’m so tired of mechanics getting over on me. Will you suggest?
There is a TSB on how the ECM (Computer) needs to get an update at the dealership. If not with warranty, you may have to pay, but it will more than likely be the cause over replacing something that doesn’t need to be fixed.
TSB # 22-NA-054
Check this bulletin: TSB# 22-NA-054
Just been through hell getting ours fixed. Goodbye Chevy!!! Hello Toyota!!!
Im getting code. And coolant temp doesn't read. Think its the temp sensor not thermostat. Cause i get heat
2019 blazer, bought used with 49000+/-miles, 2 days later shudder in shifting, goes to dealership they replace valve body and torque converter. 5 days later go visit son at college 700 miles round trip. Next day PO128 shows up steering assist disabled which leads to this thermostat/ sensor issue. Still got warranty but one service guy says drive it in - I said I’m 50 miles away if thermostat is stuck that won’t be good. Next day we call dealership and set up a tow that will fall under warranty…. Hope this doesn’t have to get uglyOnly 50000 miles . INSANE GM like this guy said DO YOUR PART,
Did you get everything figured out?
We did , but I got called to work and the wife had to take to dealership and sit and wait. Will get the invoice and info for you in a day or two. So far so good. Sorry for the delay.
Check TSB# 22-NA-054
@@scottlong7752
Will this be covered under my 60k mile warranty as i already have 54k on my 2020 blazer RS
Power steering notification and check engine keeps coming on
Did you get it fixed?
Yes took it to Japanese family mechanic and havnt had any problems since
Was yours the temp sensor or thermostat? I have those symptoms
Is there a recall for therstate
Should be
Do you mind sharing where the temperature sensor is located on the engine? Please
Sorry, just seen this, lower left under the intake
where is the temp sensor located
Left side under intake, hard to see
My wife is having this same issue now I also have replaced the sensor but 2 weeks later trips out and reads 0 until the code is cleared
We has the same issue, it will reset and be fine but will slowly get worse, try to get it fixed before 60K, if you fight it, they will cover it.
@@JamesF406 where is the temp sensor located ?
@ceasar7821 Left side, under the intake next to thermostat, you can barely see it, grab a flashlight, it's down there👍
This is happening to my 2020 Chevy blazer now two with only 50,000 miles on it. Can I drive it for a little before I get it into the shop?
My vehicle doing the same thing dealership telling me it’s not covered and I only have 43,000 miles!
So we ended up taking the vehicle in the GM, after they told us the Thermostat was bad I argued the fact that I just put a brand new one in 3 months ago, GM agreed to pay for the replacement, the Thermostat still looked brand new, it was covered under warranty and has another 2k warranty on it. If your is doing this fight it, even if its over 60K, this is a known problem and GM knows it, otherwise it will cost you around 1k to have it fixed. I should of fought the first one, Im pretty sure they would of covered that one too.
Today 10.5.23 Problem still not fixed, ECM flashed, new thermostat ( well another new one) and they are still not sure, going to change out the temperature sensor, the same one I changed out a few months ago then when that doesn't fix it they are going to replace the ECM, not good...very frustrated but they are covering it all so far.
@boxstudio1506 So, this round they changed out the temp sensor, drove the vehicle for several 30 minutes trips and the code hasn't returned yet, we'll see.
@boxstudio1506 10.11.23 GM replaced the temp sensor I just installed a few months ago and so far the code has not returned, the temp sensor cost 10 bucks....it's cheaply made.
having same issue on my 2020, so is it the thermostat or the censor? Or do i replace both?
@denisdalyaev4275 it's most likely the sensor, but, you have to tear it all apart and the thermostat is right next to it, do them both.
I’m having the same problem I have a 21 blazer
Hi James, can we speak via email or text the same problem just happened to my wife’s blazer and want to know the best way to handl this situation with gm or myself. Thanks let me know?
Sorry, did you get it fixed. 616.401.2591
You all wasting money. The ect sensor is in a harness with 26 gauge next to it high voltage which will cause interference. Thats the design flaw not the thermostat or sen
sor. Down the road it will happen again. If u do not take out the ect wiring from the high voltage harness. I found this out from a electrical engineer.
Thank you for the information. How far up through the wire harness beyond the tail end of the ECT wire connector does the ECT wire have to be stripped out? jeffberan6794 mentions to the first or second coil. Which ones are the first and second coil? Where does the feed for ECT actually feed from?
i just need to see how to take it out and replace it you’re playing with me
Sorry, I will see if I can find a better video for you.
Dont use aftermarket shit
GM SUCKS!!
It does seem like stuff is cheaper these days.