Why does my rear light keep blowing the bulb?

6 replies to this topic
  • Lennie

Posted March 15, 2009 - 11:35 PM


I dont know why my 04 Wr450 keeps blowing the bulb in the rear light, the tail light bulb lasts about one - two hours and the brake light lasts about five hours then blows.

Is there something that I can check like places where the wires are well known to get damaged? How much power should I be getting to the rear light?

I ride on the roads, dirt and supermoto so need a rear light to be legal !!! Changing the bulb every hour is crap !!! Help please. :) :banghead:

  • doctorchopper

Posted March 16, 2009 - 01:43 AM


My bulbs are blowing regularly as well, it turns out my voltage regulator/rectifier is toast. There should be around 12 volt ac, but with the revs up i was getting up to 24 v ac.

  • William1

Posted March 16, 2009 - 03:18 AM


Could also be vibration or a bad ground. These are common causes of blown bulbs on a AC system.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Lennie

Posted March 16, 2009 - 05:22 AM


I had a new voltage regulator / rectifier not too long ago and this didnt solve the problem. Also the headlight has had the same bulb in for over a year.

  • William1

Posted March 16, 2009 - 05:46 AM


Check the ground connect for the tail light. As I said ealier, it could well be a vibration issue. A change to a LED replacement may be the cure assuming the ground is good.

  • doctorchopper

Posted March 16, 2009 - 10:12 AM


With it being an AC system will it be grounded?

  • doctorchopper

Posted March 16, 2009 - 11:00 AM


Just looked at the wiring diagram and yes it does go to ground.The wire Marked B, so i'd say black or brown


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.