Bonneville America Forums Forums Technical Forums General Tech urgent electrical question

Hi all - can anyone help with this - when I was repairing the rodent damage to my wiring loom, I noticed that the rubber gromment that sits in the hole at the rear of the headlight shell was displaced, causing the wiring loom to rub on a bare metal edge. I took out and unplugged the reflector/lamp unit disconnected the snap connectors in the headlamp shell so that I could reroute the wires. Put it all back together but when I started the bike, got no dip or main beam, just the pilot. The high beam indicator lamp was brightly illuminated regardless of the switch position. I am thinking I may have a short between the high/dip beam circuits that is causing the high beam indicator to illuminate but without the wiring diagram, difficult to tell. All other electics seem OK. Is it possible to reassemble the snap connectors (i black, 1 white) incorrectly, causing this fault? Has anyone got a wiring diagram to hand?

Regards

Jan

I've got a diagram but not here at work... I'd get back into it and look it over good... check your ground in that area and your headlight connectors. It seems there were 3 wires to the headlight, any chance they got back on the wrong terminal? It's been awhile since I've been into mine and I've rewired my Honda since so I can't really recall whats what in there.

Also check to see that the fuses are ok. If there was a short one may have blown.

Jan I was just chaging a dead high beam a while back and blew a fuse. I agree with checking the fuses.

Pretty sure the connectors inside the headlight are different so you can't F it up. I like the shorted wire idea. That rubber grommet comes out way too easily. Also make sure none of the wires just plain pulled out of the back of the connectors.

Hey Jan...

OK first up there's a wiring diagram on my website. It's actually for a Bonneville/T100 but it's identical other than the connectors for the tank console & driving lights.

The main beam warning light is directly connected to the main beam, so if it's on in both switch positions you're getting power to that side of the globe all the time. I've seen this happen before in cars and it can drive you nuts looking for the cause - chances are the globe's lost it's earth connection so regardless of switch position it's trying to earth itself through both elements. First up check the fuses and the globe's earth wire - if that fails pinch a headlight bulb out of a conveniant car (any H4 bulb will work) and test that. I've seen the connection to earth fail inside bulbs if they get a bit of a knock, and it's almost impossible to see.

Matt

Thanks for this, guys...will check this out after work today. The dodgy earth/fuses sounds like the best bet so will concentrate on this line of attack.

Regards

Jan

Tah-dah!!! - And the lucky winner is.....ME! Took the headlight out of the shell and guess what - I had replaced the plug on the back of the bulb 90 degrees out (yes, it fits very nicely, thank you...) so the dip beam current was feeding back into the main beam circuit and thence to ground via the main beam indicator bulb, causing it to light up. Of course, no light from the H4 bulb as the ground was missing. When the dip switch was set to high beam, then the current from the dip circuit ceased and the high beam indicator received its current in the normal way. Doh!!! When I reassembled the headlamp first time round it was getting dark (thanks, BST) and I had been working on the wiring all day and was getting tired! Seriously, just goes to show how easily crap can happen - over the years, I must have done this job on 100's of occasions - this is the first time it's all gone pear shaped...moral of the story must be never rush to finish a job...Thanks to all who replied, though.

Regards

Jan