I have been having a very hard time keeping my lights fully operational after recovering my bike from an accident. I think most of the blame can be pointed towards my Bestem undertail that I installed. The undertail has integrated turn signals and uses 22 or 26 gauge wire which is a pain in the ***. I have solved many electrical issues following the install however I am having trouble with something new...

Long story short, the turn signals on the left side of my 2002 F4i are completely off. Under normal circumstances, all turn signals remain on and serve as running lights. No flasher relays have been installed and they flash fast. I have not had any problem with that for the past 25,000+ miles I have been riding my bike.

After installing the undertail, there would be the occasional light going out and I would find the source of the problem and rewire it or fix it. However it would only be limited to the tail light section and not the front. What concerns me now is that the front left turn signal is off as well. Another strange thing is that the turn signals work if I turn the switch on the handlebar to the left.

I have checked:
- Fuses
- Bulbs
- Wire connections in the rear

I really would appreciate some help here because for the past few weeks I have been spending more time worrying about my lights than enjoying the ride. Thanks in advance.

 

Welcome to the forum.
The only thing I can suggest is start from the source (battery) and find out where the loss of power is. Maybe pull the switch off the bars and check to see if there is any damage due to accident.

 

If you need a relay flasher unit, i have a couple spare in my toolbox as i ordered them when i put LED flashers on - but then noticed that the old one wasn't standard and then didn't end up using one - so PM me your address and i'll ship you one out, it'll take a couple of weeks to ship from Oz but you're welcome to one if you need.

And other than that just what TimBucTwo said - work from your battery, check all your connectors, check you haven't inadvertently shorted any of your wires out.

Good luck, hope you get it fixed and get back to enjoying your ride:-)

Oh and welcome to the forum;-)

 

Do you think that might be the cause of the problem? The relay flasher unit? If so, is it the one in the front near the forks or the ones in the right rear in the tail?

 

From memory - there's just the one - at the front. The thing that looks like it might be a relay is i think just a plastic cover round the rear light's wires.

Hmm, im not electrically minded - i just thought that as you'd said you hadn't changed the flasher unit - it was 1 thing to eliminate (fairly cheaply and easily) It would be really silly to spend hours trouble shooting to find it was a 5min job;-)