3rd Brake Light Out, No Voltage to it...

**jfl330** · 05-16-2011, 09:20 AM

The 3rd brake light (LED) is not getting any power. Does anyone know the path the power to the 3rd brake light takes?

I need to backtrack to find where the good power stops.

Thanks!

Jon

**cammed goat** · 05-17-2011, 06:24 AM

Usually, LEDs just burn out either at an LED diode or the curcuit board the LEDs are soldered to. When mine went, I used a Power Probe to "jump" the third brake light and it flickered, which deemed the LED bad. I ordered a replacement off eBay. I can't remember if the third brake light runs off the wiring to the tail lights/brake lights.

Do your main brake lights work?

**KMdef9** · 05-17-2011, 07:32 AM

Also, when you say it's not getting any power, do you mean you have tested for voltage at the light? How did you test it?

**jfl330** · 05-17-2011, 08:48 AM

Originally Posted by cammed goat

Usually, LEDs just burn out either at an LED diode or the curcuit board the LEDs are soldered to. When mine went, I used a Power Probe to "jump" the third brake light and it flickered, which deemed the LED bad. I ordered a replacement off eBay. I can't remember if the third brake light runs off the wiring to the tail lights/brake lights.

Do your main brake lights work?

Yes, main brake lights are good.

Jon

**jfl330** · 05-17-2011, 08:49 AM

Originally Posted by KMdef9

Also, when you say it's not getting any power, do you mean you have tested for voltage at the light? How did you test it?

Cut the leads to the LED module, measured with DMM. Zip!

Jon

**KMdef9** · 05-17-2011, 09:01 AM

Originally Posted by jfl330

Cut the leads to the LED module, measured with DMM. Zip!

Jon

Tested them against each other? Or reference?

**jfl330** · 05-17-2011, 09:16 AM

Originally Posted by KMdef9

Tested them against each other? Or reference?

Across the pair, expecting 12 Vdc.

Jon

**KMdef9** · 05-17-2011, 09:18 AM

Originally Posted by jfl330

Across the pair, expecting 12 Vdc.

Jon

Try grounding the neg lead, see if you get 12v on either of them that way. Then it will at least isolate which wire has the problem.

**jfl330** · 05-17-2011, 09:40 AM

Originally Posted by KMdef9

Try grounding the neg lead, see if you get 12v on either of them that way. Then it will at least isolate which wire has the problem.

Will do, thanks. I suspect it is not connected somewhere as I know the LR QP was replaced and wonder if the conection runs through there.

Jon

**jfl330** · 05-23-2011, 05:42 AM

Originally Posted by KMdef9

Try grounding the neg lead, see if you get 12v on either of them that way. Then it will at least isolate which wire has the problem.

The 2 pin connector in the hatch in the back rear corner was not conencted.
Took the whole back of the car apart tracing the circuit until I found that.

Someone must have pulled the LED bar out and it yanked the connectors apart, lenghtened the wires put it back together and good to go!

Jon