Thread: Fans run all the time..

I was wondering if there is a reason my radiator fans turn on when I start my car? I am using the USDM coolant sensors. :/

What kind of ecu are you running?

De ECU for now.

Hmmm. Thats interesting. I have seen this issue with chipped ecu's when either the chips were bad / place in backwards. Is the coolant temp sensor new? Have another de ecu to slap in to rule out the ecu?

No this is the only ECU I have around. Everything was fine before the swap. The fans would kick on when they needed to.

No the sensors aren't new.

I'll try and think of any possibilities of reversed wires that could cause this. In the meantime, I would try another coolant temp sensor, even if its an AutoZone special.

So I take it it's not the healthiest to just let the fans run all the time then. :/

Nope. I have seen them go bad which makes the ecu read high temps which in turn keeps the fans running. Luckily, I have had the auto zone / advance auto parts sensors work fine for me and usually run 15 to 18$. Give it a shot!

Right ill give it a try later on today. Ill probably get a more accurate timing mark with out the blow air. The VE makes it so much easier to get to!

Its not BAD. But it is a problem. Is this a new swap? Sounds just like the problem I had with my sway. I found two connectors that were not plugged in. Mine is a p11, so I dont know if your engine bay harness is the same setup. You can find the pinout here, How to correctly use a 94-97 B14 ECU in a 99 P11. Check you the continuity between the ecu and the sensor wire, I believe it is green w/yellow stripe. If there is no continuity, then you have a harness plug undone. If you do have continuity, try a new sensor. If neither work. Make sure you pull the codes off the ecu and compare them to the OBD I, or OBD II charts.