you're right.... something is shorting out

i had the same problem in laconia....break light worked fine, but had no running light

got my fingers under there and found that the bulb's blade contact was shorting on occasion and just had to fiddle around until the contact was consistent

 

Rule of thumb is 90% of elec issues are a bad ground.

 

Don't you just love it when you solve a problem? No go on out for a ride.

 

I just went through a similar problem on my Hummer; the right tail light would not go bright for brake or turn, but the running light worked. Sometimes if you'd tap or knock on the lens, it would come on for a little while, then quit working again. The socket and bulb looked perfect, both filaments looked good, there was no corrosion or dirt built up and the wiring tested out perfect. I tried cleaning the contacts and used dielectric grease and even tried WD40 and it was still only intermittently working. I swapped in a new bulb and it was golden again.

I looked really closely at the bulb with a magnifying glass and found a tiny crack on the one filament. When I would tap on it, it would re-weld itself together until vibration cracked it again. That stupid bulb drove me nuts all summer(cause I was hardly driving the Hummer at all, I was riding the bike!).

 

I just went through my TG. The fender light was intermittent as well as several bulbs on the tour pak. Picked up some Deoxit and a fiberglass pen and cleaned every socket on the bike. Everything seems to work fine now.

 

I replaced the fender tip bulbs and the tour pack side bulbs with LED's from superbrightLEDs.com . Plug in replacement, no problems, and less current draw.

 

I did, put in a few hundred miles Saturday on a poker run. Great weather and a great ride!