Hey fellow Aveo owners,
Yesterday I was driving on the freeway with a bunch of stuff in my car, so I was hard on the throttle. When I exited the freeway, the engine coolant gauge was where it normally is (just below half) but while I was sitting at a light, it started to creep up. I happened to be close to a fuel station, so I pulled off an had a look under the hood to see what was going on.
The radiator was HOT to the touch but the fan wasn't engaged. Then, the fan turned on, but only at the HIGH setting. It looks like I had lost the low speed function. Seeing as it was dark out, and it wasn't actually going to overheat (just threaten to), I headed home.
This morning I had a look at it. This is what I found:
I pulled the low speed fan relay and jumped the terminals. This should have turned the fan on "low". Nothing.
Measured the voltage across the terminals. Nothing.
Checked the "Fan Low" 20 amp fuse, it was blown. The plot thickens.
I replaced that fuse and then checked the voltage across the terminals. I got 12 volts this time.
I jumped the terminals (this should engage the fan on low), nothing.
Looking at the wiring diagram, there is a resistor inline with the battery supply downstream from the distribution block. On my car, its on the driver's side front, just under the power steering reservoir. I got under the car jumped across that resistor and got full fan speed.
Bottom line: The resistor had bit the dust. It is using open terminals (!) and looked like it was living on the Titanic for the past 9 years. I have a new one on order (GM 94812213) that I found on Amazon.
Keep an eye on your cooling system gang.