sometimes you still run into "ghost" lights where the brake lights are on dimly all the time from leakage currents. I have never proven it, but I think it comes from the ABS and the cruise circuit boards that are tied to the brake switch wire.
I could be wrong, but I think the cruise control circuit boards reading whether the brake lights are on or not isn't the case with all trucks. Earlier trucks used a physical vacuum dump switch on the brake pedal (and the clutch pedal on manual transmission trucks). I would guess that they changed this when they went from the vacuum cruise servo to the electronic setup in '93, but again I'm not sure.
I know that M-B has a similar setup, with the brake lights affecting the cruise control. Having a brake light out could make your cruise control not work, and heaven help you if you did an LED conversion.
To the more gneeral question/issue of LED bulbs...they're great for reducing electrical load and longevity, and I plan to do the LED upgrade myself at a later point in time (along with relaying the running light circuit and high/low beams). However, someone once pointed out a potential concern...since the LED doesn't get the housing warm like incandescent bulbs do, if you live in an area that snows, you may have a problem with snow build-up on the lens. Not a problem with incandescent bulbs (and not a problem for people like me who don't deal with snow
), since they heat the housing enough to melt the snow, but a potential issue with LED's. I wonder if it might be possible/feasible to add a low-level heating element to the housings to melt any snow that might get in contact with the lens, and only turn that element on in cold weather?
