Started having some issues with my 01 supercrew last night. The doors would not lock with the key fob. I thought maybe the battery was bad in the key fob and tried it a few times later on with intermittent results. I did notice a noise coming from underneath the dash after I had locked and unlocked the doors.It carried on for about 5 seconds or so and then stopped. This morning my battery was completely dead. I suspected something to do with the locks but after I boosted it and got it running I noticed the fan on the heater motor continued to keep running even after I had turned off the ignition! Any ideas what the heck is going on?

 

Are you sure it is the heater fan blowing or the fan for the CD player behind the radio. I know if your vehicle battery is low the door locks will sometimes cycle up and down for no reason. Just been thru some of this stuff lately myself.

 

Yes definitely the blower motor. It was cranked on full blast and it kept right on running after I shut off the ignition.

 

Does the radio work also? I'm thinking maybe the ignition switch is going to the Acc. position also when you turn it off.

 

I didn't try the radio as I had all systems turned off trying to get the battery charged. I didn't notice the clock on though so I think the radio shut down ok.
I just went out for a little test drive to try out my new thermostat.When I got home and turned off the key everything seems to be working normally again.Even the locks. However I sat in the truck for a minute afterwards and the ticking sound from below the dash is still there.

 

Where are you at? Has it been raining (or melting snow) a lot?

Your symptoms are ones that are often seen when the windshield leaks into the GEM module (Leaky Windshield Syndrome) or fuse box.

 

I would guess yours has a battery saver circuit? That stays active for IIRC about 45 minutes after you shut it off. I would guess there is a relay for that, but where it's at I have no clue. Just tossing this out.

 

I am in Ontario,Canada..It has been snowing a bit .Haven't noticed any water in the cab.

 

I found this thread while searching. I am also having a dead battery every now and then and it drives me nuts looking for what can do it. I actually froze my battery one night when it was way below zero and it went dead....I mean DEAD. Read thru this...https://www.ford-trucks.com/forums/4...hut-off-2.html

 

A dead battery will freeze at +20F, 100% charge good to -77F below.

 

Yep....so I know..LOL. I can't believe how fast a dead battery will freeze.

 

This is one reason why it can be problematic to try and jump start somebody. The manufacturers claim a frozen (partially?) battery can explode, don't know for sure, not inclined to test that. Probably not healthy for alternator either.