- Jul 6, 2014
- 9,267
So as some of you may know and some of you may not, my mom treated herself to a 2018 Tahoe. Long story short the only damn thing she wants that it doesn't have is fog lights. Now much like our trucks, there is BCM reprograming required and the switch has to be replaced. But the problem is, the wiring is only present from the switch to the BCM. No wiring leaves the BCM to the under hood fuse block and no wiring leaves the fuse block to the headlamp harness... Even worse is if I add all the wiring, the fuse block has a different lay out (it would seem) for fog light equipped vehicles. Being honest, this just seems excessive but whatever. Funny side story, all the wiring is there on the Sierra, actually the plug is laying right behind the knock out. It just seems like a waste of money to have several different harnesses for the same truck.
Ranting aside, I have an idea to get around GM's crappy engineering. I buy just the fog lamp assemblies, since at least the front bumper is the same for equipped vs non equipped vehicles. Then install them. Then what I do is use a weather pack splitter on the headlamp socket and use the second feed as a relay trigger to run the lights hardwired from the battery like when doing a retrofit for projectors. It is the simplest and cleanest I could come up with since the headlights are only on at night and chances are she'll be using the fog lights all the time anyway. As an added measure, I could install the correct fog lamp switch and build a latching system to turn them off from the momentary ground pulse as well... My only real concern is the voltage sense with all the electronics and if the truck has a load that it isn't expecting, will things freak out... I really doubt it but it is a thought that crossed my mind. Any opinions and input are appreciated.
Ranting aside, I have an idea to get around GM's crappy engineering. I buy just the fog lamp assemblies, since at least the front bumper is the same for equipped vs non equipped vehicles. Then install them. Then what I do is use a weather pack splitter on the headlamp socket and use the second feed as a relay trigger to run the lights hardwired from the battery like when doing a retrofit for projectors. It is the simplest and cleanest I could come up with since the headlights are only on at night and chances are she'll be using the fog lights all the time anyway. As an added measure, I could install the correct fog lamp switch and build a latching system to turn them off from the momentary ground pulse as well... My only real concern is the voltage sense with all the electronics and if the truck has a load that it isn't expecting, will things freak out... I really doubt it but it is a thought that crossed my mind. Any opinions and input are appreciated.