First post on the forum so hello to everyone. I have a 2003 and have been experiencing ac issues which have led me to issues with my cooling fans. First off, my fans will not come on due to the car being warmed up or the ac being turned on. The car is not overheating so i'm not concerned about that. My problem is with the fan not coming on when the ac is turned on. The ac compressor works and the clutch is working 100% There is Freon in the system. I have tested all the fan relays and have determined they are good. When I disconnect the coolant temperature sensor both fans run like they should without a coolant temperature sensor. What else am I missing? I have heard of a bad ground coming from the fans to cause this issue. But both fans run without the coolant temperature sensor...so how would a bad ground allow the fans to run? ANY help would be appreciated, thanks!

 

Hi FF, and welcome to the forum.
First off. let's make sure I understand the problem correctly. It sounds like the fans run only if you disconnect from engine coolant temperature sensor, is that right?

 

That is correct.

 

I've seen that once before turned out to be a bcm issue

 

I have been reading of people saying that. What is the bcm issue?

 

Unfortunately they go bad over time like anything else. Not saying that's your issue but it could be. Electrical gremlins give me fits . By chance do you have any check engine light on?

 

I don't have any CEL on at the moment. I'm just unsure about this whole issue.

 

It should throw a cel code when you unplug the sensor

 

When I uplugged the sensor it was for maybe 2 mins. I tested it to see if the fans were bad, or if it was another issue. The fans started up so I plugged it back in, restarted the car and the fans were off again.

 

Does anyone know of any ecm/pcm issues that could cause this?