Did you find out what the issue was? My wife’s is doing the exact same thing.

 

Any Luck?

Oddly enough, my wife's 2014 Acadia started doing this exact thing this week. Went left the house and within a block the a/c died. Came back home, shut off the engine and the fans were on full blast after the engine shut down. We gave it a few seconds, started it back up, and everything worked.

A few days later she called me and said her a/c died again and that her temp gauge was at the bottom (this was after about 30 mins of driving). When she got home, I put in a new thermostat. Drove it around for about 10 mins and the car stayed at 210 on the gauge (as it should) and the a/c worked fine. This lasted for 2 days and then it went back to dropping the water temp, killing the a/c.

My thoughts are of course electrical. The temp gauge can't fluctuate that drastically without it being some sort of circuit/relay/sensor issue. I think something is throwing a bad voltage, confusing the car and it is dropping the a/c; just like it does when the car gets too hot, except this isn't a 'too hot' issue.

Let me know if anyone has found out anything, I plan to call the dealership today. We purchased this new in 2014.

-Steven

 

Any updates on this issue? We are having the same problem

 

Temperature sensor

 

My 2014 Acadia has the same problem. I am going to change the coolant temp sensor out this morning and will let you know if this fixes the problem.

 

Yes, my 2014 Acadia was doing the same thing, when temp gauge would drop the a/c would quit.
after ready a couple online post on how the system operates, this is what I see. when the temp gauge drops the controller does not know what temp the engine is so it goes into protective mode. It turns the a/c off in case the outside temp is below freezing to protect the compressor from damage. It also turns on both cooling fans in case the engine is overheating. This is why the fan turns on and may run after the car is turned off. With the temp sender being the possible cause I decided to replace it. The sender is located on the front side off the front head between the #2 and #4 cylinders, under a silver protective cover. When changing the sender out I did not want to have to drain the coolant, so in removed the filter and dumped the dirt out of my shop vac. and placed the hose over the radiator fill neck on radiator and held a vacume while i replaced the sender. this did suc about 1/2 gal of coolant out which I topped off with new coolant. I took the car for a test drive and the temp gauge worked like it was supose to and the a/c cool again!!!

 

Is the temperature sender the same thing as the temperature sensor?

 

Anybody figure it out

My 2014 GMC Acadia Just started do the same exact thing!! Temp gauge drops to straight down, Fan blowing full and loud, A/C still Blows but Not cold and the recirculation button flashes. Kind of odd that it is the 2014's that have started doing this. Another way for GMC to make up spend money.

Hope someone figures it out and it is an easy fix. Please Share if you do!!

 

My wifes 2019 Acadia just did this today. Going to check the sender and see if thats the fix on this model as well

 

Did you end up fixing
The problem? My 2019 is doing the same thing. I don’t know what to do with it.

 

I had the same problem. Temp gauge stops working and A/C stops too. With a little searching on google and right here found the Coolant Sensor to be the solution. I think it was a $30 part from Oriley's. It took less than an hour to change only because I took the plastic cover off to check the radiator level and to get the wire harness out of the way. I like a clear path when working on my car. Bungee to hold the wire harness out of the way (not under much tension!)

A 19mm deep well fit right over

Remember there is a plastic tab that must be removed or pulled back to actually unplug the sensor (I broke it 😩) hope it doesn't wiggle loose. I did apply a small amount of dielectric grease to the plug, which i usually do with electric connections.

View from the top. The silver boot is covering the sensor right next to the oil dipstick

I hope this helps anyone who runs into the same problem. Super easy fix.

 

Crazy. My 2017 Acadia started doing it last week while on vacation in Florida. Did it on our way back. Drove from Ft Walton Beach to like 5 miles to Kentucky and needle dropped all the way down. Pulled over at the Kentucky welcome center rest stop to shut the car off. Popped the hood, everything was cool to the touch after like 9 hours of driving. Went to restart it and the engine was revving up like my foot was on the gas. Turned it off again. Waited 5 min. Wouldn’t start or turn over, waited 5 more, same thing. Waited about 10-15 minutes then it started.
How does an ongoing issue from 2014 - 2019 continue to happen!?

 

So, it looks like you guys have nailed it on the 2014 Acadias ---- Engine Coolant Sensor needs replacing. I am helping a neighbor with a 2017 that appears to have the same issues ---- dash temp gauge reading cold, radiator fan running continuously from start-up and air conditioning running warm. Also have a warning on the dash saying "Steering Assist is Reduced" and a P0128 check engine code that says "Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temp). I suspect this is still part of the same issue, because they all showed up at the same time. GMC must've made a major engine change around 2016-17 because the engine compartment looks completely different than what I'm seeing on your enclosed videos. And I can't seem to find any videos or chats on the 2017s. So, my main question is "Where is the engine coolant sensor located on these newer engines?" I hope no one else is having this problem on their 2017 through 2019, but I hope someone knows where to start looking for this sensor. I don't really care to go ripping off all kinds of engine covers just to find it.
Thanks,
Gene

 

I actually have a 2017 Acadia Denali and mine started doing this exact same thing about 6 months ago, but a couple days later, everything went back to normal. I read on this forum that the Coolant Temp Sensor was the main problem on the older models, so I went to the GMC dealer and purchased a new sensor. I figured I would wait until it problems happen again, and then change the sensor. However, the Acadia ran great all summer, until last week, the temp gauge dropped to 0, the air blew warm, the rad fan was racing, and the "Steering Assist is Reduced " warning came on the dash. I drove the car the next day and in the middle of my drive, everything started working again. Then last weekend, I finally had time to replace the Coolant Temp Sensor. It is not in the same place as everyone says for the older models. It took me 3 hours to find it, but I finally did and replaced it. It is actually on the top of the engine, left side under the air intake cover. I thought everything would be fine, but then today, all my problems came back. Now I'm puzzled, what is wrong with these that this problem keeps coming back? Do you think its the thermostat?

 

You're right Paris289, the coolant sensor wasn't on the radiator. The parts breakdown that speleos send me was for a Denali and I was working on an SLT (sensor on top of the engine like you say). Thanks in any case speleos, it got me looking and thinking in the right direction. So, finally changed it out after pulling the intake manifold to get a better shot at it. Still had to use makeshift tools ---- I could get a socket on it but not an extension straight in ----- probably some kind of a special extension would have done it, but it wasn't in my toolbox. Got the job done, started the engine and still the same problems. I couldn't clear the trouble codes (P0118 Engine Coolant Temp Circuit High and P0128 Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temp)). I have two different code readers (one is a TOAD software on my laptop) neither one would clear the codes. So, I finally gave up and gave the vehicle back to the neighbor lady and told her to take it to a shop. She texted me the next morning that on her drive into town, everything went back to normal. When I got my code reader on it, all the codes had cleared. Magic? Now when I hear what you have to say Paris289, I wonder if it's really fixed. Still leery about the thermostat code, but I can't even see where that is ---- someplace low on the engine where it would be a bear to try to get at.
If anyone has some more input or experience with these vehicles, I'd be interested to hear your story. How long have temp sensors been on vehicles? 1920s, 1930s, the 40s for sure. And they very seldom failed. You would think that they would have figured out how to make them last more than 4 or 5 years by now. OK, I'm done with my rant. Someone else's turn!

 

If you wanted to know where the Sensor is on the 2017, its #54 in this diagram.

 

If you wanted to know where the Sensor is on the 2017, its #54 in this diagram.
View attachment 10265

Numbers and source of the diagram are unreadable in this attachment - even when enlarged using the browser zoom function.

 

Thanks Genesmachines. I feel confident that the problems will come back for the Acadia, as mine have now come and gone several times over the last 9 months. I think my next try is a new thermostat? if anyone has any additional information, please share.

 

OK, I just replaced the thermostat and Im still having the same issues. Did anyone else go through this? How did you fix it? Im thinking its electrical?

 

Hello, I am experiencing the same issue and was wonder if you were yet to find a solution for the 2017 Acadia? I’m puzzled as well along with the GMC dealership who’s had my car for a week dropping it of 3 different times for that same problem. Please help me if you have found a solution to this ongoing Acadia problem. I can’t believe this is happening, it’s such a nice truck!

I'm really surprised the techs aren't looking at a BCM communication problem. It's the BCM which controls the instrument panel (IP). The BCM is the final link for displaying messages and telling gauges what they are supposed to show you.

 

After replacing the thermostat, my issues were still there, but after driving the vehicle for a short time the next day, the gauge started working, A/C started working and check engine light finally went away. I have been driving the vehicle since and it has been running good for about a week now. Im not sure if the thermostat fixed the issue, but right now all is good. Ill let you know if the problems come back.

 

Ive had the same issue you were having and replacing the T-Stat did infact fix the problem. If it hasn’t returned yet I would have to say that its pretty safe to assume that was the culpfit. Definitely keep us posted to any changes but fingers crossed I think you should be ok.

 

I have a 2017 and had the same problem earlier this year- I was on vacation and was taking to a nearby dealer and the problem just went away. I plan on trying thermostat replacement. For those of you who did the thermostat replacement, where is it located?

 

I have a 2017 acadia thts doing the same thing. I just bought a new temp sensor but i haven't replaced it yet. Not 100% sure it will fix the problem. Seems to be an intermittent though. I dont see how a new thermostat would help either because it happens right at first start for the day when the engine is cold. the "steering assist" message comes up right away. Fan kicks on. Any suggestions would be greatly appreciated.

 

Dont waste your time with the sensor. Bite the bullet and replace the thermostat. That will fix the problem. It doesn't seem right, but I replaced my sensor first and still had the problems. I then replaced the thermostat and I've been driving the vehicle for 2 months and have not had any issues. I wasn't to optimistic about replacing a mechanical item to fix these issues, but it worked.

 

Ok thnx. I'll have to get one. I was also wondering if the body control module might be an issue. Thought about getting one and reprogramming it. It got to be one of those three things.

 

I’m late to the game on this but was recently having the same issue with my wife’s 2017 Acadia. The mobile mechanic replaced the battery terminal and it’s been all good ever since then. This was after I suggested replacing the thermostat so I saved quite a bit of money. Just wanted to share in case it could help someone else having the same issue (steering assist reduced, thermostat on C, engine reviving, and no AC).

 

What battery terminal did he replace?

 

2017 Acadia Denali 3.6, Just had same issue, coolant temp reading 0, fan running full speed, steering assist reduced warning. I first replaced thermostat, which is doable, but not an easy task. Located on top of motor passenger side. Have to pull air Intake to get to it. Able to separate radiator intake pipe at the thermostat housing elbow and did not have to pull the fuel rails.

This did not resolve the issue. I then had to tear it all back apart to change the engine coolant temperature sensor which is located right next to thermostat housing. I suggest if you change thermostat just go ahead and replace this, as it is $15 and not much work while you have it torn apart. Dealer wanted $900 to replace thermostat. Took me 3-4 hours and cost $175 for both thermostat and sensor. Took 2 hours the second time I tore it apart for the sensor. After all that it did not resolve issue.

I then saw where one guy had battery cable replaced and I really just thought it may be a ECM issue at that point. So I went out and unplugged negative battery cable for about 10 minutes to reset ECM. And that worked, for now anyhow.

I’ve had several other electrical glitches with this car, like door locks not working right, brake lights staying on, etc. So I’d say if you are experiencing any issue with the 3.6 engine Acadia, unhook negative battery cable for 10 minutes which reboots ECM. Now here’s hoping that my issue does not come back and that this solution helps someone else.

 

2017 Acadia Denali 3.6, Just had same issue, coolant temp reading 0, fan running full speed, steering assist reduced warning. I first replaced thermostat, which is doable, but not an easy task. Located on top of motor passenger side. Have to pull air Intake to get to it. Able to separate radiator intake pipe at the thermostat housing elbow and did not have to pull the fuel rails.

This did not resolve the issue. I then had to tear it all back apart to change the engine coolant temperature sensor which is located right next to thermostat housing. I suggest if you change thermostat just go ahead and replace this, as it is $15 and not much work while you have it torn apart. Dealer wanted $900 to replace thermostat. Took me 3-4 hours and cost $175 for both thermostat and sensor. Took 2 hours the second time I tore it apart for the sensor. After all that it did not resolve issue.

I then saw where one guy had battery cable replaced and I really just thought it may be a ECM issue at that point. So I went out and unplugged negative battery cable for about 10 minutes to reset ECM. And that worked, for now anyhow.

I’ve had several other electrical glitches with this car, like door locks not working right, brake lights staying on, etc. So I’d say if you are experiencing any issue with the 3.6 engine Acadia, unhook negative battery cable for 10 minutes which reboots ECM. Now here’s hoping that my issue does not come back and that this solution helps someone else.

The Engine coolant sensor is right next to the thermostat housing. It is on passenger side, on top center of engine. If you stand on the passenger side fender well, you can see both the thermostat housing elbow and the sensor. If you are having these same issues, you should try disconnecting the negative battery terminal for 5 minutes or so and see if this fixes your issue.

I have a 2017 SLT that was having the same issues. So before diving into the whole ECT sensor/Thermostat pool I decided to look at the battery terminal issue. I found a bit of corrosion around the negative terminal, I removed the terminal and cleaned it really well and replaced it. Its been about a week and that seemed to solve the issue, so anyone having this problem I would try this first. It may not be the same for everyone but it seems to be working for me. Also I found a GM service bulletin on this issue, it says it may be the sensor but may also need an ECM software update. The electrical issue may be the cause of a lot of the headaches people seem to be having with what seems to be a common problem. Here's the service bulletin # if anyone is interested 17-NA-390.

(mod edit: added link to cited bulletin)

 

Hello. I also have a 2017 SLT and I am struggling to find the Engine coolant sensor. Can someone post a picture or a decent diagram to help me out? Also, can someone share the part numbers for the thermostat and sensor. Thanks!

 

The Engine coolant sensor is right next to the thermostat housing. It is on passenger side, on top center of engine. If you stand on the passenger side fender well, you can see both the thermostat housing elbow and the sensor. If you are having these same issues, you should try disconnecting the negative battery terminal for 5 minutes or so and see if this fixes your issue.

 

Is it one of these ?

 

Here is a picture of the sensor, the thermostat assembly and the location of both the thermostat housing and sensor located right beside the housing. it it kinda hidden under the intake on the passenger side. The thermostat house runs from the passenger side to the drivers side and then 90's and head toward the radiator and attaches to the upper radiator hose. Maybe if you can find the upper radiator hose and follow it, you can fin where the thermostat housing is, and the sensor is literally about 1 inch from it..

 

View attachment 10625 View attachment 10625 View attachment 10626 View attachment 10627

Here is a picture of the sensor, the thermostat assembly and the location of both the thermostat housing and sensor located right beside the housing. it it kinda hidden under the intake on the passenger side. The thermostat house runs from the passenger side to the drivers side and then 90's and head toward the radiator and attaches to the upper radiator hose. Maybe if you can find the upper radiator hose and follow it, you can fin where the thermostat housing is, and the sensor is literally about 1 inch from it..

Also, i guess i should add, i have a 2017 Acadia Denali, and apparently there are two different motors in that year, depending on which one you have, the other engine that is different than the one I have, the sensor is located in the front of the motor down low.

 

The 2017 Limited is NOT a Denali. The two shouldn't be confused. The Limited is an SLT-based Lambda platform Acadia.

 

Of course and understood.
It may be confusing to some including the OP. He just mentions "two engines".
Regardless some such as OP may not know about the Lambda vs C1xx platform change.
At any rate. . if the battery is below the rear floor. . . that would make it Lambda based old platform.

 

Ok. My 2017 acadia has been doing this intermittently off and on for a year. Lasts about a week. It just started doing it again today. So after reading this forum I tightened the negative and positive battery terminals without removing them and it didn't help. I tried staring it a couple more times and it still gave the power steering assist message and no a/c. So then i took off the negative terminal and cleaned it. Than i took off the positive terminal and cleaned it. Tightened the fuses next to it also. Put positive back on and tightened. Than negative back on then tightened. Sprayed battery protection on them. Started it back up and everything works again. I tried starting it 3 more times and it works great. I think the terminals are the ticket. Just wanted to share my experience

 

Did this work for you? I have a 2017 Acadia Denali and after reading everything on this forum I have taken both positive and negative cables off and removed all corrosion. The car would run great for about a week and then the corrosion would return and we would have to do the same thing again. It's mostly on the negative cable. I'm wondering if I have a bad battery... any thoughts?