Mechanics: what's your method of finding electrical faults?

[loic2003]

Symptons:

My bike has two brake/rear light bulbs that work together. For some reason, the left light keeps blowing. The right one is fine. They're connected in parrallel.

Secondly, the bike goes through stages where the fuse blows. It'll start ok and the lights will run, but I *think* when I apply the brake, the fuse pops (so annoying...). A couple of weeks ago I replaced the blown lightbulb and had a look around that area of the loom but all seemed fine. The left rear light lasted a week and only today did the fuse blow.

So I'm a little perplexed. At first I thought it could be the bulb working loose and touching the two contacts making a short, but the bulb was securely in place, and if it was shorting, the other bulb wouldn't work.

I've just picked up a multimeter/circuit tester which I'm going to mess around with this weekend, but any ideas/suggestions on the procedure to find an electrical fault would be of great use.

Cheers.

 

[QuitBanningMe]

wrap the fuse in foil😉

 

[loic2003]

Originally posted by: QuitBanningMe
wrap the fuse in foil😉

Awesome plan, then I'll melt a section of my loom which'll be even more fun to find! 😀

Currently I've just got a big ol' family pack of fuses under the seat to keep me going.

 

[QuitBanningMe]

Seriously all I can say is up the amps on the fuse.................

 

[woowoo]

Use the OHM meter to trace down the short.
(With power off)
Trace the circuit from hot to ground.
Draw the circuit if it helps

 

[malbojah]

Set the multimeter to ohms and measure resistance across the two bulb contacts. If you get any, your wiring is frayed somewhere in the loom and is rubbing together. Or it could be a bad socket.

<--ran into this problem on my trucks cap brake light where it would blow the fuse everytime I hit the brakes.