I was told at a stoplight that my brake light was out so I backed up to a some glass so i could see for myself and sure enough my right brake light was not lighting when I pressed the brakes. When I turned on the headlights however, the lamps did light up on both sides. Correct me if Im wrong, but isnt the brake light bulb the same as the one that illuminates when the headlights are on? I also noticed that when the brake pedal is depressed for a sustained time while the headlinght are on, the 3rd brake light and the working left brake light will flicker and fade... not good. I dont believe this is a battery issue b/c the headlights stayed bright and true as the brake lights flickered. Has anyone come across anything like this before or know some steps thet can help me trouble shoot and maybe come closer to pinpointing the problem before I have to take my car to the dreaded dealership?

Thanks,
Dean
05 MCS

 

I think that the stop/brake lights use a dual filament bulb, which would explain why the stop light didn't work while the tail light did. This does not explain why the lother lights flicker and fade. Change the bulb and see if the problem goes away.

 

ill give that a shot, any advice on getting that damned bulb tray out?

 

The bulb is indeed dual filament (1157). For an '05, remove the bulb holder panel by two tabs on the sides (I think you squeeze the tabs towards each other). Unplug the connector first to make it easier. No tools are necessary.

 

Have you done the rear fog light brake light mod?

 

I just hit this same issue. My right side brake light is out, but running lights still work. All bulbs and even bulb tray have been replaced and it didn't seem to resolve the issue. I did do the fog light/brake light mod as well.
On top of this, my reverse light is out as well. (04 MCS)

Deano - Have you checked to see if your reverse lights are out?

I was told the module may have gone out. How do I get to that?

 

For your reverse light, the most likely problem is the switch. Look at this thread for the repair: https://www.northamericanmotoring.co...rse-light.html

If your fog light mod damaged the body control module (BCM) computer, unfortunately there isn't much you can do short of replacing the module ($$$). It is located behind the side panel in the passenger footwell but it is a single unit, not designed to be repairable. As a sanity check, try swapping your left/right bulb trays and see which bulbs light up.