Rear parking lights.

[dbranger94]

So, I had a lady stop in my driveway when I got home this evening. She told me my tail light was out. I thought she was crazy, but sure enough my passenger taillight wasn't lighting up. I checked the turn and stop portions of the light and they worked fine. So, I thought I'd check the wiring connector and make sure it was ok and didn't have a loose wire or something. It was good. So, I pulled the light out to check the wires going into the lamp itself. Also good. I looked at the wiring diagram for the taillights and saw they both had the same connector and pinout, so I plugged the passenger light into the drivers side connector and it worked fine. According to the wiring diagram, the park LEDs get power from the BCM and the stop/turn LEDs get power from BCM-B. I also noticed that the section of the BCM that controls the park lamps had constant power. So, I disconnected the battery while I put the taillight back in the car. When I hooked everything back up the light worked like normal again.

So, if you have this happen to you, disconnect the battery. This will cycle power to the BCM and hopefully your light will work like normal again.

Sponsored

 

[Dominant1]

Good info thanks for posting!

 

[ronemca]

Last year when I upgraded my front signals to switchbacks I was unaware of this, and it drove me nuts for about 10 minutes whilst I swapped bulbs back & forth trying to determine whether:

a) I had a defective incandescent
b) I had been sent a defective switchback
c) one of the two sockets had picked that moment to fail
d) I had suffered an occlusive cerebrovascular event without realizing it

So...good tip!

 

[dbranger94]

It looks like there are FET transistors in the BCM that power the park lights in the taillights. For those that don't know what this means, the FETs simply act like tiny relays that have three connections. One is constant power from the battery, one goes to the LED to be powered and the third is used by the BCM as a 'switch' to activate the circuit. Electrical 'noise' can cause these transistors to operate strangely. I may check to see if the voltage to the BCM is 'clean' and also check the output to the park lights.

On a side note, is it just me or does everyone's tail lights make a slight buzzing sound when on?

 

[ronemca]

...On a side note, is it just me or does everyone's tail lights make a slight buzzing sound when on?

It's just you. You are experiencing a cerebrovascular anomaly, and should lie down immediately.

:lol:

I had my head in the trunk a half hour ago (engine and ACC off, but residual power probably still alive) and I heard that sound too. I figured it was the SUB in STANDBY mode, but that's only a guess.

 

[dbranger94]

It's just you. You are experiencing a cerebrovascular anomaly, and should lie down immediately.QUOTE]

Wouldn't surprise me at all...

Sponsored