I have a 2013 Cruze eco. The coolant fan runs at high speed as soon as the key is turned on, and will not stop until the key is turned off. A/C is off, and engine is not hot, yet the fan continuously runs at full speed. How do I troubleshoot this problem?

Thank you

 

I forgot to mention in my original post that I do not have a check engine light on. Also, the car runs and functions OK. Only problem is the fan continuously runs until the is turned off regardless if the engine is hot or the A/C is on. Any help trouble shooting this is appreciated. Thank you

 

I just learned one more thing. My AC compressor won’t turn on now. So basically the fan runs wide open when the key is turned on and the now the AC doesn’t work (and no check engine light). Any suggestions on how to trouble shoot this is appreciated. Thank you

 

The situation you describe sounds like the car thinks the coolant temperature is too high, or a/c pressure is too high. This defaults the cooling fans to full on, and disables the a/c clutch. If you have a coolant temperature gauge does it read normally?

 

Do you have an engine temperature gauge, and if so is it showing hot?

 

I have confirmed the engine temp is not hot. Also, coolant level is full and there are no leaks. As I mentioned, the coolant fan runs at max speed as soon as the engine is turned on, will not stop until the engine is shut off. Also, the AC compressor will not turn on. I was able to get the AC compressor to turn on by jumping the relay, but it would not blow cold air. Alll this suddenly happened yesterday. Before this happened, the AC was working fine and blowing ice cold air. Any help troubleshooting this is appreciated.

Thank you

 

What we are saying is it sounds like a faulty sensor circuit, possibly the coolant temperature sensor. You know the engine is not physically warm, but the ECM may not think that. Sames goes for the A/C pressure, there is a pressure sensor that could do the same thing. If the a/c is not getting cold when the clutch relay is jumped you may have an actual a/c pressure issue.

You possibly have some other temp sensors that may act the same. I know you said there is no check engine light but there might be a pending code pointing to the problem. Or if not you will have to look at the pressure and temperature inputs with a scan tool or some electrical testing.

 

Either it's the ac switch, or coolent sensor. I'd suspect the sensor, but if the ac won't come on, with switched on, check fro voltage at the compressor clutch, and isolate from there.

 

Disconnect the negative battery cable and reattach after 15 mins. If that doesn't work, it's probably the sensor on the rad

 

Based from the discussion, I also think it is the sensor on the radiator or the thermostat.