Hi Everyone,

My car wouldn't start one morning and the battery was completely shot. I got a jump and got it started and realized that my radiator fan would be on no matter what. So I looked at how that circuit worked and determined a few things (let me know if these are wrong.)

• None of the 4 coolant temp sensor talk to each other. (Fan while car is on, fan while car is off, ECU temp, and the signal to the dash)
• The one by the upper radiator hose is responsible for turning on the fan if the car is hot when they key is off.
• The fan timer module controls how long the fan stays on and takes a signal from the switch.

So I first tested the switch at the upper radiator hose with the car off (and fuse for the fan pulled) with the car stone cold to determine if the switch was stuck on. I used a multimeter to check for continuity and got no continuity.

Then I plugged the switch back in to test it with the fuse in and the key off. When I unplugged the switch the fan remained on, so I determined the switch wasn't the problem. I tried to read the circuit diagram and figured that my fan timer module was shot and was being grounded somewhere where it shouldn't be. So I purchased another one and replaced it but am having the same issue. I also swapped the fan relay with another one and still had the issue. What am I missing? Thanks in advance.

The car has 273k miles on it and at worst case I'll just wire in a toggle switch somewhere and turn it off every time I get out of the car.

 

First, which fan is running when the car is off and "stone cold"?

Can we assume this is a 4 cyl car - sorry don't know my Acura's that well.

 

Sorry yes its a F22B1, same set up as the 97 Accord EX. And it's the drivers side fan.

 

driver side fan = condenser fan
passenger fan = radiator fan

does the radiator fan ever run ? the upper radiator switch only turns on the radiator fan

it's possible the condenser relay is stuck closed

 

Wow, I'm an idiot I just assumed that was the case because the other fan wasn't running. Also I was looking at it today and now neither fan runs so I'm doing see if I'm getting 12V at the connectors, and if I am replace the fans, then check the condenser relay. If not, I'll do some more digging and report back. Thank you!