Have spent hours trying to identify the problem and am all but ready to take it to a shop. figured I'd see if anybody on here has a better idea first.

Bike: 2005 Dyna FXDCI

All the troubleshooting I've done so far:

Brake light does not turn on but running light does. I have made sure that the second filament is not permanently on, it's just the running light.

Neither the front nor rear brake levers activate the light

Have switched with a new bulb, doesn't work.

Have installed the entire rear light assembly onto my buddy's bike, where it worked fine. (unhooked my brake and turn signal plugs from the little circuit board near rear light and put the circuit board onto his bike, connected his clips into that board and it all worked).

Checked wiring that goes into rear brake switch to ensure it's getting a current, which it is.

Checked under fender to make sure no wires are chewed up.

Checked all fuses, none blown.

Put dielectric grease all over connectors. although it shouldn't matter seeing how my entire rear assembly on my buddy's bike worked fine.

So basically i've eliminated the rear portion from being the problem, can't be switches because neither of them activate the light, and it isn't the switch not getting a current.

What am i missing? figuring it has to be something under the seat.

Thanks for reading

 

Power is switched (via ignition switch) to both brake switches - then passed on to the rear light when either brake lever/ pedal is activated

Is there power on the upside of each brake switch

Stated another way

Is the switched power circuit..., live once the the ignition switch is turned on

DC volt meter or trouble light will help determine this

=============

Shotgunning

Could be ignition switch
Could be shorted wire after the ignition switch - feeding brake circuit
Could be shorted wire feeding ignition switch
Could be bad fuse..., or loose / corroded fuse (I know you said you checked em.., but still)
Could be loose / corroded connector (the do get that way)
Could be bad / loose / broken ground

Never seen an electrical problem yet - that wasn't a PITA


Ghost

 

You have to do a little digging and looking,, but this page with links helps alot;
https://www.hdforums.com/forum/dyna-...-part-1-a.html

 

I installed HD alarm then had local dealer program




Dealer test rode, processed paper work and I left.


two hundred miles away, this included night riding, I noticed brake lights where not working.


Went to different dealer and service tech immediately said bike was not programed as a two light bike. FXDB


Dealer charged me 10.50 and everything OK

 

Try jumper wires to bypass existing wiring to lights