ECTS or BCM

[jeepmedic]

I have an 07 Saturn QuadCoupe Ion with 146k on it and it has been a good car for the most part I get the random airbag light once every three months but just ignore it and it goes away.

The new wrinkle is the temp gauge drops to zero and the AC quits working but will later fix itself. Google being my friend points to a ECTS but it also has randomly resolved and started to work again and is currently working normally. The hitch is I have a Scangauge II hooked into the OBDII to track mileage and while the current issue is going on there are no codes and the temp is showing about 190* F which is normal. So if the OBD II is getting the right info about the temp then it cant be the sender? can it? Which I guess points to the BCM AKA $1000 VS the $12 ECTS. I have yet to inspect the connections and wiring that will happen this weekend. Anyone have any insight?

 

[bigdav160]

I have yet to inspect the connections and wiring that will happen this weekend.

The most likely cause is right there.

 

[Mowerpan]

Thermostat. When these motors do not get up to temperature as quick as it should( which is usually around 210 degrees) the temperature gauges will go to zero and shut the a/c off.
On the newer vehicles their will be a warning also that says engine hot a/c off even though the vehicle is not getting hot but the vehicle does this to protect it self.
If your thermostat is original I would change it first. <-GM Service Advisor