Headlight help

[Snareguy]

1979 XS1100
I just bought a new to me xs1100 and im trying to restore it before I cut it down to a cafe racer. Current problem at the moment is my headlights and turn signals. Headlights won’t work and turn signals won’t work. Horns work and cluster lights work. I remember once the headlight indicator light lit up but i had the headlight unplugged. I already switched the fuse box to a blade style and bypassed the reserve lighting device (hopefully i did it right). And still no voltage to the headlight or turn signals. The bulbs are good they actually look new. Im suspecting the headlight relay is bad? Any way i can test this out or just bypass it?

[bikerphil]

The bike has to be running for the headlight relay to trigger. If you want to bypass the relay, unplug it, and jump the red/yel and blu/blk wires in the harness connector. You should then have power to the headlight with just the key on.

[Snareguy]

bikerphil nice. Straight forward thank you. I did have the bike running while chasing down the voltage but no dice. Is it ok if i cut from the unit side of the connector and jump the wires through there? Or should I cut the the line before the connectors? What should i do with the wires that are not connecting to anything anymore?

[bikerphil]

I would just make a short jumper wire with 2 male spade terminals and plug them into the harness connector, no need to cut anything that way. Leave the other 2 wires alone.

[Snareguy]

bikerphil good idea keep it clean. But would this also solve my turn signal problem?

[bikerphil]

No, do the signals light up but no flash? Ok just re-read that you have no power at the signals. Check for power at the fuse panel 20A fuse first. You may want to get a wiring diagram and trace power in the circuit up to the bulbs.

[DiverRay]

Also, check ALL GROUND WIRES!!! Most turn signal problems are ground problems. It would be a good time to clean ALL connections in the bike.

[Snareguy]

bikerphil awesome headlights work. Now on to the turn signals. I get 0 voltage to the signals. Also im confused the wiring diagram shows 5 wires from the backlight connector. On my bike there is only 3

[bikerphil]

Looks like quite a mess you have there, someone really hacked that up. I wish I could be of more help, I'm not that strong with wiring diagnosis. The last photo is the turn signal canceling unit, and I know the signals will flash without it plugged in, they just won't turn themselves off.

[Snareguy]

bikerphil i know right? Im not even sure what im looking at anymore. Will check all the grounds on the bike for the meantime. Thank you for your help!

[bikerphil]

OK, i've been studying the wiring diagram some. With the key on, first check for power at the 20A fuse in the panel, the one that has tan wires on both sides. If yes, then go to the tan wire at the round flasher relay below the fuse panel (not to be confused with the flasher cancelling unit) and check for voltage there. Report your findings.

The horn is on the same circuit, check to see if it has power. the horn button is the ground and that completes the circuit when pressed. The tan wire should be hot all the time with the key on.

Another thing to look at is the brn/wht wire at the flasher relay, check for continuity between the relay and the harness plug under the fuel tank that goes to the left handlebar switch.

[Snareguy]

bikerphil Greetings bikerphil! After my investigation i think i found some new clues. I took off the turn signal housing in the rear and i jumped them to the battery to test the housing. I know all the bulbs worked so i was wondering maybe its the housing. The rear when jumped would not light up. I jumped them by putting alligators on the thread for ground and alligator on the pin connector for power. Nothing.

my front turn signals turned on when jumped.

horns have always worked ever since i bought it.

tan lines through 20amp on fuse box is live.

brown wire on flasher relay connector is live.

brwn/white has continuity to brwn/white on left side gas tank connector to L handlebar controls. I still figure out why the front is not getting any power can’t be the ground in the bucket because when i jumped the power to connectors they lit up.

[bikerphil]

Ok, next I would do some checking on the left handlebar switch circuit. At the connector plug under the tank that leads to the switch, check the brown wire and the brn/wht wire for continuity. Make sure the handlebar switch is in the left position. Next in the right position, check continuity on the brn/wht wire and the dark green wire.

[Snareguy]

bikerphil i will check as soon as i get home. Quick question. How would i check continuity on those wires? I don’t know where to place the testing leads since its in an enclosed connector.

[bikerphil]

Unplug the connector and check on the handlebar switch side, do nothing with the side that goes to the rear of the bike. You are looking for a path of continuity thru the switch itself. This will determine if the power is heading towards the signals uninterrupted.