Hi,
This is my first post and I found this site trying to "Google" my problem.
There seems to be some pretty knowledgeable people here so "here goes"
I just bought a 2007 F150 FX4 Supercab and the drivers side heated mirror is not working.
I have pulled the mirror off and checked....no voltage at the mirror.
I pulled off the passenger side to check what the voltage should be at the mirror 12V (ish)
I pulled the center dash panel to check if a wire had fallen off but discovered that would be impossible due to there being just a couple of large "plug in" type connectors.
I'm thinking maybe a problem (broken wire) in the rubber boot that connects the door to the cab.
I really dont know how to trace the wire from the switch, (of if that's what I should do).
Can anyone help me?
Thanks

 

If it is just the heated mirror circuit that is broken, check the Dark Green w/ violet stripe wire in the door. This is the output of the heated rear window relay ( same relay for the rear glass and the mirrors ).

The switch is a momentary switch that pulses the heated glass input to the cluster, which grounds the heated glass / mirror relay. No need to go digging any father than the relay through Fuse # 8 to both mirrors.

 

I checked the fuse and it was ok.
The passenger side mirror heats like a charm
Would it be the fuse or relay if the one side is working?

 

Neither, it would be the wiring from the common L & R splice to the mirror head.

You need to find if the wire to the door harness ( in the kick panel ) is good and then move to the door to A pillar harness, or start in the door and move the other direction.

 

OK I'll have a look tomorrow.
Any tips on identifying the "door harness" thats in the kick panel?
When you say "kick panel" I assume are you referring to the one that houses the fuse panel.
Is there some way to get in behind of the fuse panel to locate the splice?
Would the splice be behind the fuse panel or above it?
Pardon my ignorance.

 

You could start on the passenger side, but you are not really dividing the circuit in half to see which way to go ( towards the driver's side door or towards the splice ).

Start with the driver's side, where the wires route up from the connector area to the door to a-pillar harness ( the rubber boot ). Chances are this is where the wire is broken.

 

Alright, Thanks
I'll let you know how I make out

 

Well, I've eliminated the mirror to the door connection.
I disconnected the rubber boot from the cab and checked for continuity from the mirror to the correct pin and it tested OK.

Now, Ive got the dash apart and have found the green and violet wire that comes from the mirror defrost button.
It heads into a large mass of wires.
There is no splice before it disappeared into the mass and into a harness

All the wires that enter the cab from the door are behind the emergency brake apparatus...I cant tell if the heated mirror line (green and violet) heads up or drops down from behind there, there are wires everywhere!!!
Where do you think I will find the splice?

 

The Dark green w/ violet stripe wire is from fuse #8, and goes to the heated mirror status LED indicators as well as the mirrors. This is not part of the switch, just the LEDs on the switch.

As post #4 above, there is nothing wrong with the relay or the fuse, or the connection from the fuse panel to the splice ( that is all common to both sides ).
The status LED ( on the switch ) should illuminate when you turn on the heated mirrors, with the relay being good ( post #1, you said there is voltage at the heated mirror circuit on the passenger side ).

The status LED does illuminate, correct ?

You verified one direction ( A-pillar to door connector ) , did you verify the other direction ( A-pillar connector to the fuse ) ?

The splice is under the fuse panel area, looks to run over the trans hump just in front of the seats is the route for the wire.

 

Thanks SSCULLY
Yes, the light comes on and the passenger mirror defrosts
I have not traced the A-pillar connector to the fuse yet.
I'll have to check it tomorrow (i'm off to work again}
If the problem is in the splice, can I access the back of the fuse panel somehow?

 

Shows as below the fuse panel, not behind. At least that is the 2006 location chart for the splice. 3 Dark Green w/ violet wires ( 2 wires from 1 direction, 1 from the other ).

 

Well here's where I'm at.
I have traced the green and violet wire from the fuse.
It heads directly into a large mass of wires that goes towards the rear seats, across to the drivers side, then directly into the door a-pillar connection on the drivers side.
I cut the wire at the drivers side seat area and have a good wire from there back to the fuse.
I dont have a good wire from there to the truck side of the a-pillar connection.
It must be in between the female side of the a-pillar to where I made the cut
Going to see if I can get the truck side of the a-pillar connection out

 

VICTORY!!
It was a bent pin in the drivers side a-pillar (truck side)
I had to pull off my e-brake assembly to access the a-pillar from the inside so I could pull it in to have a look.
Feels good
I think I have about 8 to 10 hours invested investigating the problem but it was worth it.
The downside of all this is that I dropped the mirror outside and it now has a big crack in it but at least it gets warm now (i tested it and the element in the glass is still intact).

Think it'll take me a while to put it all together again


Thanks a million SSCULLY
I'll have to buy you a beer sometime

 

BTW, It was very strange to find that the power (green and violet), from the fuse went directly to the drivers side mirror.
Also, the green and violet wire that goes into the passenger side mirror comes all the way from the drivers side.
It comes back along the same route as the power (green and violet), came over in the first place.
Very Strange

 

Thank you for posting what is missing in quite a few thread, the resolution.

The next member will thank you for it. Glad you got it fixed.