Originally Posted by dtp
Hopefully someone can help a bike wiring newb out with a problem here...
Verified that neither brake activates the light to rule out the switches.
Verified that the headlights do not activate the running light (is there one? I never noticed... but pretty sure there is... lol)
Verified other electrical stuff works... headlight, turnsignals, speedo lights, etc.
Changed the bulb.
Checked for continuity at the wires where the leads plug into the tail lamp assembly and there is none there when the brakes are engaged.
Checked the plug next to the battery where the leads come out of the main wiring harness and go back to the rear of the bike. I do get some continuity there when the brake is engaged but I don't know for sure if I am checking for the right thing here... but perhaps this is pointing to a cut wire somewhere behind the harness.
Not sure what you mean by no continuity and some continuity.
What are you using to test this.
The fact that there is no tail light AND no brake light suggests a bad ground to me. I've had to fix the ground wire more than once on my 40K mile '95.
IRRC this is the Black/white wire.
If you have a test light connect one end to ground (the battery negative terminal is the best place) and touch the other end as close as possible to bulb's contact for the brake light. Better yet take out the bulb and touch the contact inside the socket. When you operate the brake with the igniton switch on the test light should light up.
If it doesn't start working back along the W/B wire until it does light.
If the test light indicates power into the brake light contact then move the grounded end of the test light to the + terminal of the battery and and start probing with the test light from the ground connection of the socket and work back to the actual ground connection. When you have a good connection the test light will light up.
Disclaimer: This is based on looking at the DR350SN wiring diagram. I could give a better description of where to probe if I looked inside my tail light, but it is below zero out there and I'm NOT going out to look.