Harley Brake Switch Diagnosis

Bob LaRosa has reviewed the brake light switch issues at the handlebars and underneath the transmission clutch cover. Here he gets into the brake light switch diagnosis with the Haynes repair manual to trace the issue with the color wiring diagram. The rear brake light stays on constantly on this motorcycle and though it’s nice to have a bright light covering your rear it’s just not safe.

To start the diagnosis, he has the wires out of the loom and he removes the rear brake light switch under the trans clutch cover to eliminate that being the failure point. Now we have a better idea that the issue lies in the handlebar switch or in the harness. You will need a standard test light and your Haynes repair manual to get you through this process. Verify your test light by putting it on the negative and test to the positive to make sure your test light works.

Bob will show us several tests using the repair manual’s color wire diagram to trace the correct wires, where they go and how they connect. Use all your resources to make the job easier and more understandable. Electricity can be funny but it also can be fun.

Get your Haynes Repair Manuals online.