I have a 2012 superduty Lariat. When the outside temp drops below 10 below the blower fan wont come on. Today it was -27 I went and started it up and drove for 30+ miles and it never came on. I let it sit for a couple of hours and the temp warmed up. I went and checked it and it came on just fine. the local dealer checked it the last time it did it and they said it showed no codes. I left it at the dealer overnight so they could check it in the morning but it didn't get as cold that night and worked. What could be causing this to happen? Never had a problem with it last winter or this summer when it sat in the sun and was 100+.

 

Just a stab in the dark..... issue with temp sensor and/or circuit, HVAC module possible bad solder joint(s), expanding and contracting with temp swings? Or, the electrons in your truck unionized and refuse to work under those conditions Sorry I'm no help.

 

That's what I was thinking but the dealer said no codes came up on the scan. Today it was 7 below went and checked it and it came right on. After I drove it yesterday and then let it sit for about an hour it came on. So a sensor of some sort makes sense.

 

I'm having the exact same issue, Rick2204. I was thinking it might have something to do with the crazy weather lately here in Ottawa, ON - many thaw and freeze cycles - wondering if moisture could cause this? It starts working once things warm up

 

Well it finally didn't work for the dealer and they replaced the blower motor under warranty. They couldn't say what was wrong just that it. I thought that it might have been the weather too but when it didn't work for them it was about 10 above.

 

After a bit more research on F150 forum and Youtube, it turns out that the problem was a very common one for this truck- a flakey connection at the blower motor resistor behind the glove box. I can wiggle the wires and have the blower turn on and off. Very accessible - looks like a relatively quick fix. Cheers.