Hey just as stated. My radiator fans are not coming on at idle, causing the radiator to overheat. Steam coming from the cap. The car gauge is in the middle though. When I unplug the sensor though, they both come on. What can be causing this? I think the relay is good. Any negative side effects if I just leave the sensor unplugged so the fans stay on all the time?

 

what sensor are you unpluging, is it the temp. sensor? cause it sonds like you have a bad temp sensor. I'd start there being that its only a few bucks & very easy to replace.

 

thanks a lot guys. Seems to me my relay went bad, thats the only part I have not replaced yet. The rest is it could be faulty wiring or its just getting plain old. Oh well... thanks everyone.. this site rocks

 

if the fans come on then its not the relay, its the temp switch . cost about 15 bucks.
letting the fans run all the time is alright to get by temporarly, but its not good to leave like that...besides the part is cheap and easy to replace so just do it! haha

 

My fans only come on at idle during certain conditions, not all the time.

The ECTS may be at fault as stated prior, but is the steam coming from the cap if left alone and sealed?

 

yeah the steam is coming from the radiator cap. I read somewhere on here that it is supposed to do that once it reaches a certain pressure, like a safety thing.

The 2 switch's that sit on the coolant line on the engine to the right of the intake manifold have been changed with the one's from the old motor so thats not the case. I tried with new ones and old ones.

 

So, you're assuming the sensors from the 'old' motor are still good?

 

they worked fine before, the fans i mean. so yes the original sensors should be good, nothing wrong with the sensors that i replaced probably either. The ac fan does not even come on, when i turn the ac on. However once I remove that grey plug from that sensor the fans both turn on right away. The relay had a little burn mark in it, so i thought that was it for sure, now i replaced it and still nothing!

 

I put some refrigerant in the car, and now they work. How does the AC system have any effect on the engine cooling system, not to mention the "electric"fans? i just keep on learning stuff with this car. amazing....

 

well your a/c was probably to low to alow the compressor to come on. your fans come one when the a/c comes on to pull air through the condensor. since you added freon and got the a/c to come on ,now the fans come on as part of the a/c system.
your symtoms still indicate a bad coolant temp sensor