Re-program for Top box brake light?

[hefy_jefy]

While I have the topbox in bits I decided to add the brake light. The BMW part is v expensive so I decided to go for another LED solution. However there are dire warnings about the need to reprogram if the BMW light is added. A bit of testing shows that with the ignition on I see about 6.5v at the connector and with the brake applied it rises to full voltage about 13v. Pushing my luck a little further I connected a regular 8.5W filament bulb. Nothing at 6.5v; in fact with the bulb connected I saw zero volts across the lamp, but with brake applied all was well, full voltage and a bright lamp. Also no warnings from anything that I could see. Does anyone have the BMW lamp? Does it have a low (running light) and a high (brake light) function?

Geoff

[Nomore76]

Geoff - I installed the BMW light kit when I had the top box apart for painting. It was a simple plug in procedure. There is no running light. The LED lights work only when the brake is applied.

[hefy_jefy]

OK Bruce - thanks! Just what I needed to know, I wonder why the 6.5v when only the lights are on - hmmmm...

[dirtrider]

OK Bruce - thanks! Just what I needed to know, I wonder why the 6.5v when only the lights are on - hmmmm...

 

Evening hefy_jefy

 

Lots of open circuits show some stray voltage. Put a little load on the circuit & see if that 6.5 volts goes away (probably will).

 

Voltage with no current behind it is misleading & fairly useless as a test reference.

[hefy_jefy]

Indeed there's no current behind the 6.5v because it falls to zero with the filament bulb across it, I wondered if it had something to do with fault detection...