My brother in law has a couple month old 21 stx. He's been having some bad electrical issues, where radio and heater and such will cut off, then come back on later, airbag lights on, windows rolling down by themselves. Odd things. And been having condensation on inside of windows. He had a taillight lens busted for a couple months on it, hit by a rock. He took it to the dealer and they told him the busted taillight was causing all his issues. $900 to fix. How would a taillight cause such problems?

 

Haha. Probably a 21 parked in purgatory with the windows down.

 

Short answer is yes, broken taillight lenses can cause issues if they are getting water or condensation. One of the easy things to check when weird things happen. The ones I’ve heard of had BLIS in them but it probably doesn’t matter. Learned this chasing down similar electrical issues in my truck, was not the cause in my case.

 

When I took the pickup bed off of my 2019 F350 before installing the flatbed, I started it and drove out of the shop. None of the heater controls worked, nor did a whole bunch of other crap. Removed the taillights from the body and plugged back into the chassis, everything worked fine.

 

On a similar note, it's well documented here and I've lived through it on a 2017 I had - the plug up in near the spare tire can get water intrusion/corrosion and raise hell with all kinds of things from the HVAC controls to the stereo head unit to the window controls.

 

That seems so strange that a place that is so easy to get corrosion can affect main systems in the truck. With the airbag light on that seems like a major safety concern. His taillight was still working, just the side of lens was busted and he hadn't had a chance to order a new one yet. I just thought that very strange!

 

If I remember correctly from back in spring 2018, the airbag light would also come on when I stepped on the brake along with the other gremlins I previously mentioned. It was pretty crazy stuff.