I am at a loss on what is the reason for my cooling fan not coming on. I have replaced all the sensors both A and B. The fans will run if I jumper switch A with ignition switch on or if I turn the AC on. Car runs and idles great but the temp will rise while idling after a long drive and fan will never turn on. I replaced the fan timer module behind glove box too with a used one from eBay. This car is new to me and I believe its been a issue before I bought it. I just replaced the head gasket timing belt and water pump because the car overheated while my son was driving up in the mountains and didn't notice the temp climbing. I can turn AC on and the temp will go back to normal. Does the coolant sensor for the ECU control the fans at all? this is the only one I haven't changed.

 

if you can jumper the fan on then the fan switch itself is the issue, get one from Honda, check the connectors for breakage or corrosion

 

Edit: actually it's possible the new fan switch isn't turning on if there is an air pocket there...crack open the bleeder bolt that faces the sky and let the air out, close it, check if the fan turns on after warmed up

 

I have bled the system till a steady steam comes out. If a air pocket exist wouldn't it overheat all the time? As long as air is passing thru the radiator it stays a 1/4 below half. Could it be because I didn't use OEM Honda sensor switch? If I jumper the switch with car running should the fan come on like it does with the key just in the on position?Thanks

 

model and brand of the fan switch you bought ?

 

I ordered a new sensor switch for the radiator cooling fans. I switched out the one I got from local parts store with a OEM part. I took the car for a test drive to warmer her up and then parked and let her idle. The temp gauge slowly moved up to just above half way and I was gonna shut her down but waited a little longer and the fans came on and brought the temp back to normal. The question is this normal now? Should the fans have turned on sooner? Both of the switches I had bought do not give the temperature range what is the temp that this switch should close?