- Dec 16, 2011
- 557
Ok, so I've been trying to fix this minor cosmetic annoyance for a little while and all I've managed to do is chase gremlins.
When the park lights are off and the brake pedal depressed, between 4-5 volts backfeeds to the park light circuit. This backfeed causes the last two rows of LEDs to illuminate on the front bulbs. They then turn off when the brake pedal is released.
I've ruled out the following changes (tested one at a time and tested once with all changes except the front LED bulbs):
*Modified tail light boards as being the source as this continues when I swap back in the OEM boards.
*Rear LED bulbs have been ruled out. It continues when the incandescent bulbs are swapped in (both in the OEM and modified boards).
*Flasher. It persists with the OEM and LM487 flasher
*Front LED bulbs. Here is where it gets interesting.... I tested several sets of LED bulbs, including transferring the middle pair from the rear to the front. Depending on how the bulbs were manufactured, either all diodes light up dimly or just a row or three.
*Rear load resistors, removed them, no change to issue.
*Jettt DRL killer. Temporarily set back to stock, no change.
*Unplugging the rear circuit boards altogether didn't change anything. Issue persists.
*Added 6ohm-50w load resistors to the brake light circuit in the rear (at recommendation of v-leds), no change. I pulled the resistors off my cavalier for this test rather than purchase new.
The bulbs that I am running currently are all from V-LEDs (some test sets up front were purchased from superbright)
The front bulbs are 3157 5k white/amber type two switchbacks
Rear brake/turn when rear OEM board is used is 3157 7w red.
So now I'm a bit lost. I'm not opposed to swapping back to incandescent in the front, but only as a last resort.
anyone have a nudge in the fix direction they want to share?
When the park lights are off and the brake pedal depressed, between 4-5 volts backfeeds to the park light circuit. This backfeed causes the last two rows of LEDs to illuminate on the front bulbs. They then turn off when the brake pedal is released.
I've ruled out the following changes (tested one at a time and tested once with all changes except the front LED bulbs):
*Modified tail light boards as being the source as this continues when I swap back in the OEM boards.
*Rear LED bulbs have been ruled out. It continues when the incandescent bulbs are swapped in (both in the OEM and modified boards).
*Flasher. It persists with the OEM and LM487 flasher
*Front LED bulbs. Here is where it gets interesting.... I tested several sets of LED bulbs, including transferring the middle pair from the rear to the front. Depending on how the bulbs were manufactured, either all diodes light up dimly or just a row or three.
*Rear load resistors, removed them, no change to issue.
*Jettt DRL killer. Temporarily set back to stock, no change.
*Unplugging the rear circuit boards altogether didn't change anything. Issue persists.
*Added 6ohm-50w load resistors to the brake light circuit in the rear (at recommendation of v-leds), no change. I pulled the resistors off my cavalier for this test rather than purchase new.
The bulbs that I am running currently are all from V-LEDs (some test sets up front were purchased from superbright)
The front bulbs are 3157 5k white/amber type two switchbacks
Rear brake/turn when rear OEM board is used is 3157 7w red.
So now I'm a bit lost. I'm not opposed to swapping back to incandescent in the front, but only as a last resort.
anyone have a nudge in the fix direction they want to share?