My son and I bought a 1985 K100.  It does not have the front fairing, and therefore no front turn signals.  The rear turn signals are solid when we turn them on, and we are trying to put on LED turn signals on the front, just to get it legal so we can register it.    LED's on front turn signals are not turning on when turn signals are turned on.  

I am new to working on motorcycles, so may not know all of the terminology or how to properly explain problems and issues, so sorry in advance.

Sounds like a good parent/child project.

Not sure what "solid" means in regards your rear turn signals. I take it to mean working ok ( but probably flashing too fast).

LED lamps are tricky in that they will not work if wired in reverse... Positive and negative must be correct, but no damage done if connected wrong. Try reversing the two LED connections.. If still not lighting check supply with volt meter ( or check LED connected direct to 12 volt battery).

Maybe when you do get the fronts working they will still flash too fast to be legal. If so there is a fix for that . 

Good luck.

First, verify if the previous owner removed the turn signal relay located inside the fuse box/wiring box under the back of the petrol tank. Listen for clicks or humming when the indicator switches are pressed (61 31 1 459 224 is the relay's part number). Once you know you have it search the forum for turn signal operation because using LEDs will cause a rapid flash due to a lack of the correct resistance, and you will find how to minimise the flash rate somewhat by a subtle modification to the internals. Look for a post by Duck explaining the technique.

If you open the box up as TWB suggests, the turn signal relay is the big black one. The green one that is the same size is the Bulb Monitoring Unit (BMU).

Dai wrote:If you open the box up as TWB suggests, the turn signal relay is the big black one. The green one that is the same size is the Bulb Monitoring Unit (BMU).

The flasher relay has a green case on early bikes, black on later bikes.

Loner, are the rears blinking at all or do they stay on all the time?
American slang has caused a little confusion I think.

Aw, that'll teach me to post just after I get in from work at 1.00am!!!