one brake light stays on
 

Hi all, searching left me flat on this.
My right brake light burned out. I replaced the bulb, now it is on anytime the tail lights come on, off when the tail lights are off.
I replaced the bulb socket, no joy. I would understand if it was off, but why power when the tails are on?


Thanks

Do you have any dash lights, or light warnings scrolling across the bottom of the cluster?

As an initial point of investigation I would remove the tail light, just three bolts, I think 10mm, and check the metal contacts and plastic standoffs for cracks, sinking and pitting.


Sent from my iPhone using Xoutpost.com

Yes, "Check brake lights" "Check rear lights"

Yes, "Check brake lights" "Check rear lights"

one brake light stays on
 

Sounds like the system has registered a fault. Being you’ve already replaced the socket with no luck, I would pull out the taillight and thoroughly inspect the back side. The socket “screws” into a metal plate system that provides power and ground. Those plates get hot and can melt the plastic standoffs and or pit as the bulb socket wears and arcs across to them, you’ll see small burns if that’s the case. Worst case the taillight is failing, best case you can “tweak” things back in to place or solder the burnt spots and potentially fix it. Though, with yours perpetually on, the system may have stored the fault and need reset- check for physical damage first - if you don’t see anything, disconnect the battery for about 15 minutes and let the car sit. When you go back, touch the positive and negative terminals - car side (battery still disconnected) together for 15/30 seconds and the reconnect the battery and recheck that light.

EDIT - taillight is very easy to remove, unplug the harness, leave the bulbs in, remove the 3 10mm bolts and wiggle straight out [emoji106]


Sent from my iPhone using Xoutpost.com

Double check to make sure have a the correct bulb. If you think it's right then try switching bulbs with the other side.

Thanks guys, bulb is correct. I'll try clearing the error code, then pull the tail light.

None of that worked, but now the car is in fail safe mode..........

Possibly the old bulb burnt out in such a way that the filament shorted to ground, it can and does happen. Should have blown a fuse but maybe the driver in LCM has shorted. What do you mean by fail safe ? Did this happen when you had a scan tool hooked on?

It's idling rough now like it's in "Limp home mode" the message in the dash is "Engine fail safe mode" all I did was unhook the battery, wait the touch the pos and neg cables (while disconnected)