99 Explorer, Heater Fan does not work when extremely cold

[BillRod]

Hi Guys

99 Explorer.
Heater fan does not work at any setting when extremely cold outside.
I did replaced the Fan resistor last month cause the fan would only blow on High setting but now it is very inonsistent, Not working when really cold and working when it is not as cold or warm.
Any thoghts anyone?
Thanks
Bill












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Any thoughts on

 

[MaicoDoug]

The speed resistor wiring harness & the blower motor is a popular way to address the situation. All 3 parts normally require replacement together. Available at your local parts store. Don't start in about the blend doors..... Good luck, my hvac system works great, & thank God it does.

 

[rubydist]

Most likely you have a bad connection, which works when it is warmer but not when it is real cold. I had a Courier with that issue many years ago and it was very frustrating because you don't feel like looking for a wiring problem when it is below zero out.

 

[SenorNoob]

Can you tell if it even tries to run when it's cold? Hear it hum?

 

[BillRod]

Thanks for the replies.
I'll revisit the resister block.
The replacement from Rock Auto came with both the resistor and the connector with short pigtails, I did not replace the connector. Never had to replace one before on anything.

Thanks again!
Bill

 

[scotts90ranger]

Yeah, I would look at that, some terminals get overheated and being copper they lose their spring tension and make a bad connection or the connector melts and the wire pulls out and that makes for a bad connection too...

 

[SenorNoob]

I spent a couple hours re-pinning my interior fuse block for that reason.