2009 Ford Flex Radiator Cooling Fans

Hi everyone, My wife’s 2009 Ford Flex has an intermittent radiator cooling fan issue. It has dual cooling fans and with the AC on, the the passenger side fan runs wide open but the driver side fan doesn’t run. With the AC off, neither fan runs even though I let the car idle for a long time to try and get it hot enough to allow the fan(s) to turn on. It doesn’t matter if the engine is cold or warm, the passenger side fan runs extremely fast when the AC button is pushed. I’ve checked all connections and applied some di-electric grease to the connections. I also checked the fuses to the fans. Wondering if anyone has seen this in the past on a Flex or similar Ford vehicle. From what I read, you have to buy the entire dual fan assembly. Thank you.

Thats typical of a bad motor. It happens on all brands. Its not a real common occurrence and it is random. Most likely one of the brushes in the motor is hanging up, but the motors are not meant to be repaired, only replaced. In the long run, replacement is the best way to go.

There is a remote possibility that it is one of the relays. Your underhood relay panel will probably have three relays dedicated to the two fans. They way you are describing the issue, two relays would have to be bad. If you can locate the relays and know how to read the diagrams on the relays to identify the contact, you can remove each relay, jump the contacts and see if the fan runs, or you could swap the relays around so that each relay spends some time in each socket and if the conditions change, then you have a bad relay.

But I really think it is the motor.

Awesome. Thank you for the response.

If you can swap the fan connections you can see if the other fan drives when the ac on. If it does, swap the relays and see if it runs. Next would be the temp sensor for the ecm.