Robbie Sapp

I have a 2015 F-150 Platinum that I'm having issues with the driver side mirror not heating. I currently have the tow mirrors on my truck as I installed them 5 years ago. I have the 22 pin connector and a 4 pin connector.

I pulled the top glass and have continuity on the two heating element pins. I cannot seem to get a reading on the wires in the mirror for the heating element. I tried continuity as well and received nothing, even with my rear defrost switch turned on. ​​​​I did notice my puddle light isn't working either.

My question is, where can I trace the heating wire and ground to start tracking where I may have a wiring issue? The passenger mirror defrosts just fine it's just my driver mirror. I can't seem to find out what pin is for the heating element in the mirror either.

Anyone able to help a guy out?

jamie75

I’ve even dealing with this also on my 2016. The circuit is pretty simple. Fuse 63 under the hood feeds both mirrors fed by the rear glass circuit.

I pulled the plastic trim on the door and unhooked the plug. Turned on my rear window defrost and was able to verify power. Put everything back together and it seems like it may be working now……frustrating tracing this down.

I have the workshop manual and once power is verified the next step is to replace the mirror glass

Robbie Sapp

Do you know what pins in the door plug you were able to verify power? Even using the wires that plug into the heating element on the mirror I wasn't able to verify any power. When I went to the passenger side I was able to verify about .5 mV but I'm unsure what it's supposed to be.

jamie75

mine is the 8 pin on my XLT and it was the lower left IIRC

the manual says on the 22 pin, pin 1 is power and pin 8 is ground

Robbie Sapp

Yeah that's a 16 pin, not the 22 pin. All the 22 pin schematics I have don't show me a heated mirror hot.

jamie75

sorry posted wrong one. the c521 is the plug if you google it

should still be pin 1

Robbie Sapp

Thank you! I have that pin out but didn't see "heated mirror" so I greatly appreciate you pointing out which tag it is!
Do you know what voltages I should have?

jamie75

The manual didn’t say. The recommendation is using a test light so I assume the normal 12 volts

Robbie Sapp

Thank you for your help. After doing some investigating I noted that I had a good ground on the top mirror but I didn't have any continuity on the 12 volt line in from the mirror plug. On the bottom mirror I had continuity between the positive and the negative so I just rent a jumper from the bottom positive to the top positive all works great now.