[Undead Rado]

Ok I have an issue that's been going on a while now. To begin with it all started this winter when I forgot the truck idling with the heat on high for about an hour and a half. The keys were hot to the touch when I shut it off and it was really hot inside. Ever since then it randomly shows ac off on the cluster and the temp sensor stops working. Well first guess was replace the temp sensor, didn't change anything. The more time has went on the less the ac works, temp sensor always quits reading when the air goes off. I even cut out the plug for the sensor and just wired straight in and no change. I can disconnect the battery to allow the truck to reset and when I first start it the AC works fine, a lil driving or hit a bump and it goes off. Has me stumped. Any ideas or input would be appreciated. I traced all the way to the fuse box earlier and couldn't find any shorts, etc

 

[CUZICAN]

I know this is no help, but I had the exact same problem and was never able to figure it out. I figured if it reset when I pulled the battery terminal, that it had to be either the ECM or the BCM and I wasn't spending the money on fixing it, I gave up and traded it in on one of the good days where the A/C was working.

 

[Undead Rado]

Ya I'm almost leaning that direction, been going on a while now, when it happens it still blows and all just won't work on ac just fan. I guess it's a precaution when the temp sensor quits reading. I gotta figure it out before the heat of the summer that's for sure

 

[CUZICAN]

Mine started it this past fall, so I survived the winter with no problem, but with spring and warmer weather on the horizon, it had to be repaired or replaced, there was just no way I could haul my 3 year old around with no A/C. It was explained to me that because the computer doesn't know what the engine temp is, that to protect itself from overheating, it turns off the A/C to help keep the temp down. I could have lived without the temp gauge, but the A/C was a necessity.

 

[Undead Rado]

Going to order a PCM soon and hopefully that takes care of it.

 

[Undead Rado]

Replaced the PCM and still have the issue. Going to try and trouble shoot it a lil more then it's going in the shop. My wife totaled her car so she is driving the colorado all the time now with my daughter so I have to get it fixed. Sucks that it may likely have to go to the dealership, if so maybe they will find something simple I'm overlooking

 

[Kashed Throat]

Any updates? Mine just started doing this today randomly driving down the highway, need this fixed asap...Miami sun is no joke lol

 

[Undead Rado]

No nothing yet. If your randomly started doing it the temp sensor may be the cause. I already replaced it on mine and it's still acting up

 

[tahitiansoul]

Did you check the fluid level? (Pressure in the system)

 

[Skizzo]

Would the ground block on the passenger side have anything to do with this? It is worth checking out.

 

[Undead Rado]

I will check it, I replaced the body ground by the battery a while ago, it's sounds to me like a short or something, when it has signal/connection whatever the case is the ac works great but when the temp stops reading it shuts off, blower still runs but it shuts off ac to help regulate engine temp

 

[Undead Rado]

If you ever have the issue check the blower motor resistor/plug first. I should have looked there to begin with since the floor heat comes out there. As hot as it was inside the truck with the heat on I'm sure it was very hot where it first came out. Had to order a resistor/plug kit offline because nowhere local keeps both in stock

 

[Bobby Boucher]

I've had this problem as well, the ac works more often then not luckily. After a few days, we diagnosed the problem as a stuck thermostat. I went out of town before we could swap in a new one, but have you thought of this as a possibility?

 

[Undead Rado]

Did you replace the thermostat and it fixed it? I'm still heating up to 1/2-3/4 on the gauge, not overheating either so it's not stuck shut, don't think it's stuck open but if all else fails I may try that. The code it's throwing gives thermostat as a possible fix but mine isn't acting like it. I think it's the body ground issue most people have had, haven't got to check that yet though in away from the truck

 

[Bobby Boucher]

That code is P0128 if I remember right. And my truck only showed that code once out of the dozen times it has happened.

I haven't replaced the thermostat because I've been out of town a lot this last month. I'll get to it this weekend or next week, and post if it solves the problem or not. Hopefully it will help you out.

 

[Undead Rado]

Check your blower motor resistor and plug too if you haven't already, and the fender ground on the pass side

 

[Undead Rado]

I did change the thermostat out today, I think GM assigned their biggest idiot to design that mess. I would hate to do it on a lowered truck and have to pull the tire and possibly inner fender to change out a $40 part that is about $7 for most other vehicles. I really didn't think the thermostat was an issue, and may not have been the whole time because the blower resistor and plug were cooked pretty good so I assume the fender ground caused that. After changing the resistor and plug out i cleaned the ground and put dielectric grease on the connection. It would work a few days then shut off but I finally got to watch the temp gauge and at idle it barely climbed over 1/4 in 90+ degree weather,,, so I changed the thermostat earlier and started it back up and temp ran normal, hit a lil over halfway and stayed there. Anyways I believe it's fixed now, I just gotta pick up some butt connectors because I have the resistor plug tied in with house electric twist terminals because that's all I had lol