Hi, so after some research after my previous thread, I have the following:

-No tail / brake lights.

-I know my tail light wires themselves are ok, bought an incandescent bulb and if I touch a 9v battery to the wires (not connected to the bike) one of the filaments lights up.

-Previously there was an LED bulb which did not light up with a 9v battery.

-The tail light was originally flickering / dimming when I tapped on it with the LED bulb in. Once I initially disconnected the lamp the LED bulb never worked again, so my assumption was that the bulb was failing (but maybe I'm reconnecting it wrong). Replaced with 1157 incandescent, reattached the wires and started the bike. Nothing.

-I can assume the wires running under the seat and fender to the tail light hole are good, because I accidentally let one touch the fender and it sparked a lot.

QUESTIONS:

-I only have two wires for my tail light, can I run a dual filament incandescent bulb?

-I don't know how long the circuit breakers take to reset, but it seems waiting doesn't help. Any ideas?

-Should the brake / tail light work with just the ignition on? Before when it was working sporadically neither would come on unless the bike was running.

I'm pretty sure I've tried the wiring both ways, but both the wires coming from under the fender are black and I can't tell which is supposed to be which.

'96 FXDL, and I'd be extremely grateful if anyone would assist. As far as I can tell only the tail light is bad on this bike, everything else is fine but I can't ride without that and I'd love to get out and actually enjoy my bike.

Thank you.

 

Really sounds to me like you have a grounding issue.
You need to invest in a decent digital volt/ohm meter. ($10-15 and you'll have it forever)
Hook everything back up and turn on just the headlights (running lights).
Find a GOOD ground (neg on the battery) and put neg of the meter on it.
Put meter in voltage mode (appropriate range for 12 volts)
Probe the bulb connections inside the socket(carefully, dont touch the sides!). One should have 12 volts (11-13 is fine).
Then move to the other bulb connection and have someone apply the brake.
12 volts should show on the meter.
Turn everything OFF.
Next, switch the meter to ohms (resistance).
The case of the bulb socket should be ground.
Between the case of the bulb socket and Batt negative, you should get 1 ohm or less.
This all sounds to me like a grounding issue, like the socket is not getting a good clean ground.
Hope this helps, pictures would be useful if you need more help!
Cheers and good luck

 

THANK YOU. I looked deeper under the fender and realized that there is in fact a ground wire. I reconnected it to the light itself and everything works perfectly.

You're a genius, sir. Thanks again.

 

see my original thread