Flashing hold light-no a/c-dead temperature gauge

[pavilion780n]

While driving my 2009 Aveo the temperature gauge went dead, the A/C compressor stopped working, and the HOLD light started flashing. Fuses are good and I don't see any obvious wiring (burnt, etc) issues. Anybody else have or see this problem before? Any ideas?

[New owner]

Mine did the same thing on the way home last night. 2009 Aveo LT. Everything was working fine then boom everything is out! Does anyone know what can cause this? Really don't want to go to the dealer if it is just the thermostat or a fuse. I have no cel & the car seemed to run & shift fine.

[PoisonIvy]

Lol! I'm taking my car in tomorrow morning for exactly this. I spent a while googling this over the last couple days (at work, sssshhhhh). And IT IS the thermostat. I believe GM used some cheap thermostats especially around 2008 to 2010 it seems. They start disintegrating and sticking open. Because the thermostat is computer controlled, the computer shuts down the compressor in case the car is overheating. It isn't, but because the thermostat is opening which allows coolant/water to flow and cool the engine, the car isn't sure if it's due to a heat issue. The shutting down of the temp gauge, I don't know, GM just decided to program that into it. There's also likely a P0128 code pending in there. It's because the car won't heat up as quick as it should, due to it cooling itself with the sticky thermostat. Another thing that may happen is you'll be driving and the gauge will start working again, but you'll notice that it just doesn't want to stay up to a warm temp, as you drive you'll see it really cool itself off. It SHOULD be covered under powertrain warranty, which you may or may not have on your 2009. Not that it's an expensive part, but if you don't have to pay for it... Also read some experienced suggestions to stick with the OEM thermostat, the big chain replacements have a greater fail rate. The only real negative is you'll burn more gas, but there's a chance I guess after running a little rich for long enough you could do damage to the cat.

[New owner]

Thank you PoisonIvy for the info. Helps a lot to know what the problem is

[pavilion780n]

I played with the wiring harness on my car, near the fuse block, and it started working properly again for a few days, then went back out. haven't had time to check it again. May be a wiring issue.

[New owner]

Ok thanks pavillion780n I will try that too. Just every time I take any car to a dealer they want to change things may not actually fix it. If I am just going to throw money at it I can do it myself! Since it has not thrown a cel I'm not sure that the dealership can do any better than me. Have you had any other wiring problems?

[PoisonIvy]

FYI, the dealer had me fixed up under powertrain warranty Monday afternoon. Thermostat.

Pavilion, if you unplug the power to it, it probably will reset the code and work again. I never had a true CEL on when this happened. There WAS a pending P0128 code in the system though. And with that code, it's the thermostat 99% of the time. Combine that with your symptoms of the gauge going out, a/c off, etc....... Don't believe me, google "Chevy engine hot a/c turned off". We don't have the DIC, otherwise we would have gotten this message. It's VERY common for GM's of this era.

[pavilion780n]

I will have it checked out, thanks.

[New owner]

Thank you very much for the info PoisonIvy. I got the thermostat from the dealer but changed it myself. It was a fairly easy job, just four bolts to undo & a couple of wires to disconnect. My car is now running fine again A/C and all! I live in Florida so the A/C is needed even at this time of year so thank you again!