Headlight Relay by-pass

[warfman41]

Hello fellow xs people. Haven't been on here in a while, but I knew if I had a question about an xs, this was the place to be. I saw a while back where someone on here said there was a how-to on by-passing the headlight relay. Could someone tell me how to get to the post? thank's

[bikerphil]

Locate the relay, it is above the ignition coils under the fuel tank towards the front. Unplug the 4 wire connector from the relay, make a jumper wire and connect the red/yel and the blu/blk wires together. Headlight should now come on when the ignition key is switched on.

[warfman41]

Thanks.

Hey, thank's Phil. I wouldn't mind putting a new relay on the bike, but been having a hard time finding one. You wouldn't have a good lead on that, would you?

[TopCatGr58]

Hey Warfman,

First of all, your relay may NOT be bad, but the diode on the wire that goes to it from the ALT may be, and that's possibly why it's not throwing. First, you need to check to make sure your charging system is still working. Put a voltmeter on the battery, and run the bike to 2500+ rpm, and ensure that you're getting ~14+ volts, and if so, then it's charging and you're good to go there. IF it's not getting 14 but only ~12 or less, then you have possibly found why your headlight relay isn't throwing/latching....and you should have also noticed that your tach isn't working either!

If charging is good, then you can TEST your relay. With the relay PLUGGED IN, Put a jumper wire on the White wire in the harness plug....then with the bike running, connect the jumper to a +12V source for just a moment, and then disconnect. IF the headlight comes on and stays on, then you know the relay is working, but it's not getting the signal from the WHITE wire to make it throw/latch. IF the headlight never comes on....THEN the relay is bad.

SO...now you have a choice. IF the headlight came on, you can either tear apart the harness to find and replace the diode from the ALT. OR you can wire in a switch....could be a temporary push button type...and run a 12V line to the switch, and then to the white wire in the relay switch harness. SEVER the white wire so that isn't still connected to the rest of the harness so you won't possibly be backfeeding 12V DC into the AC line! Then after you start the bike and have it running, you can THEN push the "light" button to cause the relay to throw/LATCH and turn your headlight ON. Once it's on, you don't need to keep energizing the relay, it's a latching/locking one and will keep the relay thrown UNTIL you turn the key back off.

I've done this to mine because my diode died, and I didn't want to bother tearing/chasing the diode line in the harness. I have a single pole single throw switch....but it can stay thrown IF I don't remember/forget to turn it off, and that can DRAIN the battery if left ON even though the key is off because I used a Direct non-switched 12V+ power source for the switch. If you tap into a keyed ON type 12+V power source, then you won't have to worry about having/leaving that type of switch thrown in the ON position.However, it's still suggested to have just an intermittent power signal to the relay. 3Phase/Scott posted the differences of the different years/models of headlight relays, and if you send to much voltage into it for too long, it could burn it up!?

THis way you can still start the bike without the drain of the headlight first, and then can turn ON the headlight once it's running.

OR....you can just unplug the relay, get a standard 4 terminal relay and a SWITCH....you'll need a 12+V source, a ground source, and then the red/yellow and blue/black wires as the circuit to be connected/energized by the throwing of the relay. The relay will need to be able to handle ~20amps. Then you'll still need to run the wires for the switch from the harness to the handlebar switch whereever you mount it, and then to the Relay, and also then to a ground source. Being a regular relay...not latching....you'll be able to turn ON and also OFF your headlight while the bike is running.

ALso, IF the relay is bad, charging system is good, you can check the white wire for an AC signal with that voltmeter...should be about 7 volts DC if the diode is still working. IF you get a voltage signal on the white wire WITH The bike running, then you could also look at just replacing the OEM relay....contact Andreas Weiss, he's probably got one he can sell you quite cheaply and quicly!!

T.C.

[bikerphil]

The 79F does not have the diode buried in the harness like the 80 and later models do. The yel wire is the trigger on the 79's. The early type relay is usually repairable, most likely a bad solder joint inside.