2008 Dyna fat bob.
so yesterday I'm sitting at a light, not even using my rear brake. I start to smell something electrical burning and suddenly there's a big cloud of smoke that just as quickly blows away. I pull over and check for an issue and find that one of the connections to the rear hydraulic brake light switch is completely melted off.
Today I replaced the switch. I wasnt sure if it just went bad or if there was another issue that caused it. Electrical is not my strong suit but just for fun I checked it with a volt meter. I did not connect the wires to the switch at first and I found that when the bike power is on one wire has 12v going through it, when I checked the other wire, it also had power but it was only 7.3v.
I assume the 12v is coming from the battery, but am confused as to why the other wire, (which i assume is going from the switch to the brake light) has voltage. Is this normal? Or does that mean there's a short feeding back from the brake light to the switch?
Thanks in advance.

 

Look at the wiring diagram, you will see that the Red/Yellow wire comes from both the front and rear brake lamp switch and goes to the brake lamp.

The Orange/White wire powers both brake light switches.

When either switch is made, the Red/Yellow wire will get power, illuminating the brake lamp.

 

A burnt terminal is typically caused by a loose or corroded/high resistance connection.

 

So does that mean that both wires of the rear stop lamp switch should have voltage to them?

 

The Orange/White wire always has power.

The Red/Yellow wire will be energized when either brake switch is activated.

 

Boxerguy...did you resolve this issue? If so what was the problem and how did you fix it?

 

I did resolve the issue! I replaced the rear brake switch but still had intermittent problems with it not lighting up when i hit the brakes. I also noticed intermittent issue of turn signals not working and when id hit the horn as soon as it engaged it would just cut out. I would pull the fuse for that stuff and it would "reset" and work again for a bit. While trying to track down a short thinking that was the cause I noticed when I was turning my switch from off to Ignition or Ignition to off it only had a very small area that it made proper connection, I could just barely touch it and it would lose connection. Going from Off to accessories was solid and lights and everything worked fine. So I took the Ignition switch apart and it was pretty nasty in there, old grease and green build up from the copper and just grit and grime was causing a bad connection. New aftermarket ones are about $30 but from what I was reading the tumbler for the key is different so you can't swap your original key tumbler over to the new one without modification, so would have to modify or use 1 key for Ignition and 1 for neck lock. I just cleaned mine out, gave the contact points a scrub with steel wool and some new dielectric grease and havnt had another problem with the lights. If you decide to do the same watch when you remove the C clip, they aren't under big pressure so won't fly all over but there are 3 springs in there. I'd rate it a 1 star out of 5 for difficulty. Easy fix once you track it down.

 

Wow...nice work figuring it out. I'll certainly keep this in mind when I attack my issue. Thanks!