I have a friend that has a 2003 K1200GT with Hannigan sidecar. He recently purchased a Hannigan trailer to go with it and this is the problem we ran into today.
When the trailer is on the hitch and all lights wired up, everything works fine, except for the brake lights. When the trailer is plugged in, there are no brake lights anywhere, on the bike, sidecar or trailer. Unplug the trailer and the brake lights on the bike and sidecar work fine. So, we hooked the trailer up to my Jeep and all the lights, including brake, work just fine. We hooked it back up to the bike and everything worked again, except for the brake lights. So we unplugged the harness going to the sidecar and the bike lights, including brake, worked, as well as on the trailer. Hook the sidecar back up and no brake lights anywhere.
My theory is that something in the servo ABS brakes is causing an overload condition, which is why the bike/trailer or the bike/sidecar combination work fine, but with all of them hooked up, nothing works.
I hope this is clear, we looked at it so much today that I may be talking in circles. If so, ask away and I will try and clarify. Anyway, if anyone has ever ran into this before, I would appreciate any thoughts.
Thanks in advance.