My headlight went out, and its not the bulb, or the headlight switch.

[Joester]

My ride: a 2008 DRZ 400sm.

I let my roommate ride my DRZ today and the plan was to meet at walmart, I got there first, and when he was pulling in on my DRZ im 100% sure that the headlight was working. We went into wally world and came out, but when we were leaving I looked in my rear view mirror and I realized the headlight was out, so I pulled over to let him know that he wasn't very visible.

Got home and took out the bulb thinking it burnt out, but a 9V battery lights both filaments.

So I took off the harness piece with the horn button/ blinker switches/ HI/LO beam switch on it, but after much diagnosing with a multimeter, I have confirmed that is not the problem either.

That harness with the blinker switches on it has 2 connectors on the ends of it. one end is black with 3 terminals, and it goes to the headlight bulb and the other has 7 connections and goes into the main harness of the bike. I got my multimeter out and switched the bike ON. Only 2 terminals in the connection had any voltage going through them, illustrated below.

The terminals that had voltage went to either the blinkers or the horn, Niether yellow wires (which are the ones going the headlight) had any voltage, so I'm assuming that the problem is further down in the harness. My bike has the free power mod, and Eddie's super start kit, but I doubt that has anything to do with it, I'm just trying to give the most info I can about my bike for the best diagnosis.

There's only one fuse on the bike, which I haven't checked, but if it was blown, there would be much more than the headlight that wasn't working, right?

heres a wiring diagram, I'm not the best at reading them, so anyone who can and sees anything please let me know what to check. I really don't want to unravel the whole wiring harness just to fix my headlight. Thanks for any help or suggestions.

Wiring diagram located here: http://i619.photobuc...ringdiagram.jpg

EDIT: here is a BETTER WIRING DIAGRAM... http://www.cmelectro...uki-drz400s.jpg

ANOTHER EDIT: My horn works. The part of the wiring diagram bewlow indicates to me that it is something "downstream" from the horn, right? If the wire was broken at the yellow, my headlight AND horn would both be broken. If the problem was somewhere like the blue line, my horn would work but my headlight would be out. Is this correct?

EDIT: If I have to, how hard is it to tear into the main harness? I really want to eliminate some unnecessary stuff like my clutch switch, kickstand switch, The extra wiring not necessary because of the free power mod, etc, but how hard is it to get involved with that? I'm afraid once I unravel the harness I would never be able to get it back to what it was like from the factory.

Edited January 23, 2012 by Joester

[Stu28]

I recently had a problem with my brake light not working. I'm no electrical genius, and advice on here was that it was the wiring.

It turned out to be a problem with the wiring.

You should get some good advice on here

[Joester]

yeah, I'm hoping so. I'm definitely no electrical genius either haha.

[Noble]

The start button turns out the headlight when pushed. Your problem is probably the switch contact ion the start button or the button is just sticky.

[Joester]

thats a very good observation ill go check that out.

[Joester]

I feel really stupid right now. Noble was right and I disassembled all that stuff for nothing. Crusty start button it was, I'll probably take it off tomorrow and get a wee bit of dielectric grease in there just to make sure its all good in the future. Thanks for pointing that out, I will sleep soundly tonight knowing my bike is all healthy.

[Stu28]

It's a good learning point, and a good learning point on the forums. I know I have learnt loads on here.

[Noble]

You see this same problem with Hondas and other motorcycles that turn out the headlight with the start button. Suzuki added thus feature to the S when the SM was intorduced.

[jussenuf]

Same problem here, and was puzzled that both hi & lo were out. Fuse was OK. Plugged it back in and it worked. I did not notice when I pulled it that the plug was loose. Had worked out due to poor routing of the clutch cable. Added a sip tie to keep the cable off the connector and no problems since.

Art