Dynamo Light problems

briano101

Hello,

has anyone had a similar problem with dynamo bicycle lights? My front ligh t works off the dynamo fine but the back light doesn't!
I had the back light checked by the manufacturer and it is working fine. So obviously there is a problem with the mudguard providing a good circuit for the back light? Does anyone know of a way to check the mudguard for conductivity /circuitry?

The wires from the dynamo on the front wheel check out fine until the back socket of the mudguard.

any ideas appreciated

regards
briano101

Lumen

The solution may depend on your dynamo and front light setup, but if you're having problems earthing it with a single wire you can use a twin wire, which will earth it back through the front.

BostonB

A auto electrician would probably sort it in a minute. even a mechanic.

Al Wright

A frequent problem with rear light directly fitted to a chromoplastic mudguard. Cause of problem can be broken link conductor or connecting stud making poor contact. (keep a lookout for special offer 10 euro multimeter from Aldi or Lidl, I found it invaluable in tracing dynamo faults)

The following CTC thread may be of some use
http://forum.ctc.org.uk/viewtopic.php?f=5&t=17072&p=135989&hilit=mudguard+mounted+rear+light#p135989

Civilian_Target

What's the dynamo type? Dynamos lights that earth to the frame are pretty fiddly about this - if you can link it to ground with a cable instead, it's usually a more reliable way to do it.