Headlight Issue

[Wheelieboy]

The headlight on my DRZ400SM sometimes does not turn on...

Usually when I cold start the bike, the headlight is off...then after a bit of riding (10 mins or so) it turns back on. It seems to me that a connection somewhere is loose or dirty but I cant seem to find out where. I've cleaned all the connections on the plugs near the headlight cluster of wires already but the problem still persists.

When I flick the low/high switch, the highbeam light does not light up on my dash either.

How should I go about finding the culprit?

I found a diagram on thumpertalk, I dont really know how to read it though....and I'm not 100% sure it pertains to my bike but someone posted it for the DRZ400E

 

[Brian P]

The dashed black and white wire (possibly black with a white stripe?) is ground - it's common to many different circuits. The other two wires are one for low beam, one for high beam.

If neither low nor high beam work then it's safe to assume that the problem lies prior to the handlebar switch.

The red wire that leads to the connector for the switch is the power wire. It also feeds a number of other functions.

Next time this happens, test your horn and your brake lamp. They're fed from the same circuit. If the horn and brake lamp also don't work, the problem is in the power feed circuit ahead of that. If the horn works but the headlamp doesn't, the problem is either in the headlight switch or the harness and connectors leading to it.

 

[Wheelieboy]

The dashed black and white wire (possibly black with a white stripe?) is ground - it's common to many different circuits. The other two wires are one for low beam, one for high beam.

If neither low nor high beam work then it's safe to assume that the problem lies prior to the handlebar switch.

The red wire that leads to the connector for the switch is the power wire. It also feeds a number of other functions.

Next time this happens, test your horn and your brake lamp. They're fed from the same circuit. If the horn and brake lamp also don't work, the problem is in the power feed circuit ahead of that. If the horn works but the headlamp doesn't, the problem is either in the headlight switch or the harness and connectors leading to it.

The horn and brake lamp works.

I took the headlight switch out and a look at the it and it doesnt look like anything is broken...maybe next time it happens I'll put a multimeter to it.

I was also reading something that a sticky ignition switch can cause the the headlight problem as the headlights turn off momentarily while the starter is running.

I dont think anything is really broken though as the headlights eventually turn on, from the vibrations I guess?

 

[Brian P]

If your headlamp turns off while cranking, that is not the right wiring diagram. There is nothing shown in that diagram which would accomplish that.

Check your starter button switch. On a bike with a relay to cut off the headlight while cranking, a stuck starter button will keep the headlight off until the button unsticks. The other symptom will be that the starter motor keeps running ... but once the engine is running, that's not always audible.

 

[frekeyguy]

Think on that bike the head light comes on as soon as you turn the ignition to the ON position ?- when starter is pressed it will turn off - after motor cranks over - it should turn back on.

Question: when you turn your key to the ON position - does the light come on always ? Or does it only turn off after cranking the bike over ?

 

[Wheelieboy]

Think on that bike the head light comes on as soon as you turn the ignition to the ON position ?- when starter is pressed it will turn off - after motor cranks over - it should turn back on.

Question: when you turn your key to the ON position - does the light come on always ? Or does it only turn off after cranking the bike over ?

From what I remember last time, it did not turn on when I turned the key.

 

[frekeyguy]

From what I remember last time, it did not turn on when I turned the key.

Run a extra ground from the headlight into your battery negative. Or even better do a continuity test to the frame ground or negative terminal.

Or just stick a piece wire into the headlight harness and run into your negative. If you now turn your key on - you'll know it's a grounding issue to your head light bulb.

Work your way back into the harness.


Have you done the simple thing and swapped in another bulb? If the filament inside is broken after vibrating itself - it might stick back into place.