head light woes

[sparky30]

what would cause me to blow the head light fuse as soon as i turn the key on.I havent done anything different from last yr.this is the first time ive had a head light issue. thanks in advance

[DGXSER]

Sounds liek a wire or connection has corroded and is shorting out to me. Try disconnecting your actual headlight and see if it repeats from there. then work your way back one connector at a time in the circuit to see what it is.

[fredintoon]

Hi Sparky,
the fuse blows not when the engine starts but immediately, when the key is turned on?
Most likely there's a short circuit from the headlight wire to ground. Look for a wire that's had it's insulation worn off and is touching the frame or a wire that's gotten trapped under a bracket or a clamp and it's insulation has been squeezed off over time.

[dbeardslee]

If you look inside the headlight bucket the connector that goes to the ignition also has a blue lighting wire in it (hmmmm, ignition and lighting). I had to redo it on mine. I'd look there first.

[3Phase]

Sparky, if it's a '78E you most likely have a shorted handlebar switch.


Looking at the schematic:

The headlight fuse feeds a Red/Yellow wire.

The Red/Yellow wire goes from the fuse box to the headlight relay, then up to the headlight On/Off switch on the right handlebar switch.

After the switch it comes back down as a Blue/Black wire that runs down to the RLU to turn on the lights when the engine is not running and there is a junction with a Blue wire that runs the instrument lights.

If it's not the handlebar switch, happy hunting.


Regards,

Scott

[Brad]

Again, I'm not a mechanic or expert, but I had the exact same problem and I found mine was in my harness between the harness and frame on the left side, a wire grounding out. Take off your headlight, turn your key to the on position and even if your fuse is blown use a meter and check for continuity (or if your meter make noise, a beep) on all leads to the frame. You should only have one that registers, the ground. Also check from your blown fuse connection to the frame, then check from the in and out wires from your switch to find which one is toast. I re ran a new wire from my fuse box to the switch in my bars. Hope that helps.

[sparky30]

Thank you all for the input....I found the prob,it was a short to ground.insulation worn....

[DenyP]

Ya, been there, done that last year. Mine was intermittent and was a PITA to chase down!

Deny

[3Phase]

Thank you all for the input....I found the prob,it was a short to ground.insulation worn....

Right on, sparky! That makes it a little easier to find than unwrapping the wiring harness or disassembling the switch!


Regards,

Scott