I noticed that my brake light wasnt working. The running light seemed to be fine but when I squeezed the front or rear brake no change. I assumed it was the bulb, so I went purchased another. Come to find out the bulb was just fine, and in fact I noticed that both filaments were burning all the time. A little investigation and looks like the rear brake switch is bad. It actually failed closed not open. A voltmeter shows constant contact across the switch all the time. Any one else ever had this switch fail closed?

 

I had the same problem but it was my front switch inside the controls. I'm not sure about the rear but the front switch is a "normally closed" switch, meaning in normal position the circuit is closed, when the switch is pressed it opens. When your front brake lever is in the normal position(not pulled) the switch is being pressed down by the lever so the circuit is open. When you pull the brake lever the switch is no longer pressed and is in the normaly closed position which energizes the light.

If you take apart your front control without following the instructions in the manual and install a 4mm shim you ruin the switch. So if you have touched your front controls you may have ruined a switch. These switches are super cheap chinese junk. I have broken several just testing them and Harley really gives us the middle finger and charges about $50 for this B.S. that cost them $1.

 

My front brake did that, but it wasn't the switch, the lever wasn't coming back to sit on the micro switch. HD says I need a new actuator kit for the reservoir, but i know the switch is loose in the housing and i can adjust by placeing a spacer between the switch and the back of the housing. the retainer got loose the first time i broke the end of the switch while replaceing my brake lever. Just like Big KevO mentioned.

 

Sorry for the hijack but my lever does not return all the way either. There is always some slop in the lever. The manual says to add brake fluid to correct this issue but my level is correct. I must need a new "actuator kit". Thanks for the tip maddghost. If that stupid switch costs $50 I'm afraid to ask how much the actuator costs.

 

Been my experience sticking gets that one. It gets slow and the electrical contacts do not snap apart and they stick together. Be sure when you change it to bleed out that opening, screw it in and bleed caliper. Use proper sealer and correctly if you use sealer. I normally use none but watch it closely for a few day to make sure I have no leaks. It's NPTF thread on mine (National Pipe Tapered Dryseal) I have replaced mine twice in 40K. The front once.