[rookyDiy]

Hi folks, adding some information about how I diagnosed this issue because it took me a long time to figure out due to a misunderstanding where I thought that the taillight has just two halogen bulbs (and was *not* LED);

Bulb: 12V 21W 64136 (fog light and possibly emergency break light)
Bulb: 12V 16W Reversing light

My problem was that I started with the wiring diagram at https://f10.5post.com/forums/showthread.php?t=2026682 where the right-inner-tailllight shows just two lights;
- Tail Light (LED symbol)
- Dynamic Break Light (halogen symbol)

I still don't know why it does not show the reversing light but with this missing I ignored the LED symbol! I focused on the '12V 21W 64136' bulb that didn't light when the brake was pressed. I did not know it was mainly a fog light and unfortunately didn't test fog lights.

This led to hours of googling wiring harness issues and FRM that can cause this issue. After some googling, I thought this bulb must be used at a low power setting as the running light and with smart electronics, also lights when the brake is pressed hard at > 50km/h.

It was only when I looked at spare parts that I saw part number 63217203226 describing 3 light sources, including LED! I then realized that I needed to focus on the YEL and BRN and measured the voltage at the connector to be a healthy 14.8V (not a wiring issue then). I verified that the bulb holder 63217263536 reads 14.8V between nodes that power the LED (opposite side of the reverse light). I found it simple to swap the left inner light to the RHS and found that it does light on the right hand side (need to remove the fog light to do this test).

So finally I narrowed the problem to the LED taillight 63217203226 and am off to the scrapyard to pick up a replacement. Hope this saves someone for the same misunderstanding - there were LED's back in 2010 !

PS
I now know that the actual wiring for inner-right taillight is
BRN Ground to 'right side of cargo area'
Blue/ thin black stripe: power for reverse bulb (16W)
BLK/WHT(10) Fog & Dynamic Brake light power (21W)
YEL Tail light power (LED)