Greetings...I'm looking for some assistance with an issue with the tow mirror marker/signal lights on my 2019 F250 XLT. The mirrors are factory installed, power fold/telescopic, heated, with the puddle lights and marker/signal lights. The passenger side had to be replaced because it was cracked so I opted to go the aftermarket route. I initially installed Morimoto XB lights and had issues with hyper flashing on the signal function and the running lights were not turning on. Morimoto advised they have sometimes seen the lights throw codes to the BCM upon initial install and they would need to be cleared or the BCM reset for the running lights to work and resolve the hyper flash. When I was getting my routine service done at the dealer they didn't see any codes come up. Dealer gave me the sideways, confused dog look when I asked about a BCM reset and simply told me no as it wasn't their problem. After leaving the dealer I noticed the drivers side marker signal was no longer functional at all and only the passenger side was working, still with the hyper flash. The issues could not be resolved and Morimoto ultimately stated sometimes is happens and refunded money back.

I researched and came across Boost Auto Parts tow mirror lights that had excellent reviews across the board. I ordered those and installed. The passenger side is working perfect with the running light, signal and spot features. The driver side is only working as a running light and spot. It has no turn signal functionality at all. I called Boost Auto and they were concerned with it being an issue with the lamp and sent a replacement. Installed the replacement and same exact issue.

I started troubleshooting the drivers side lighting issue and it looks like the 22 pin connector on the inside of the truck by the A pillar that connects to the mirror's wiring harness may not be providing power on the signal wire. The pins look good and were cleaned for the heck of it and the connectors look good. I know for a fact the driver side was working properly with the OEM marker light prior to removal but now it lacks the signal functionality as well if plugged back in.

I'm not sure how to narrow down the issue. I see a lot of lighting issues posted up being caused by BCM DTC codes so I ordered an OBD2 scanner specifically for Fords to try to check for myself. It supposedly will catch B-body codes caused by lighting circuits and will allow them to be cleared. I have no experience with OBD2 scanners so not sure if a code being cleared would resolve or if no code is thrown if a BCM reset should still be done.

What else could be causing this issue? A short or wire issue somewhere else? Fuses were all checked and good. I was researching the Drivers Door Module but can't determine if that control the signal function in the tow mirror light.

Any thoughts or advice to point me in the right direction would be greatly appreciated. Thank you!