One for the electrical sleuths…

[OldButNotDead]

 

I recently noticed my horns not working. I’d run a hot wire and relay to drive these a few years ago, so guessed the relay went bad. Swapped it out today, and still no horns, but some twilight zone stuff I’m at a loss to understand.

 

With the ignition key in LOCK or OFF, a press of the horn button causes the horn relay to click. No horns, so I’m thinking I will need to check wiring between the relay and the horns. BUT…why is the relay (driven off the original horn wire) even being activated with the key in the LOCK or OFF positions??

 

Now it gets weirder. If I turn the key to ON, pressing the horn button no longer causes the horn relay to click, instead the oil and alt idiot lights come on.

 

Otherwise, the bike seems to function normally. The last electrical work I’ve done was to swap some bayonet-style lamp holders into the instrument cluster.

 

Any takers?

[emry]

Sounds like a grounding issue. I would get out the meter and do some voltage drops and se what is going on.

[Kiwi_Roy]

It's really tricky troubleshooting from here but thinking about it you say " If I turn the key to ON, pressing the horn button no longer causes the horn relay to click, instead the oil and alt idiot lights come on"

I would try first to figure out why the oil and alternator lights don't come on until you press the horn button, perhaps once you have solved that the horn problem will become obvious. It seems to me the horn circuit is providing the 12V that should be provided from Fuse 5, the headlight circuit.

 

Tell us a bit more about the horn relay you used, it wouldn't by any chance be a 3 wire type or you have a regular one wired with 3 wires would it?

I'm thinking that with the key off you are powering up one end of the coil from your "Hot Wire", the other end is connected to the horn button (where the horns originally connected). When you push the button the power flows from your "Hot Wire" back through the relay coil to ground through some of the other loads on Fuse F5 for example the headlight filament.

 

Actually I would be checking for a broken Red/Black wire between the large plugs at left and right just at the front of tank, perhaps where it flexes with steering, there are several spots where other wires are spliced into it. Check both Left & Right plug and sockets for corrosion also.

From memory the R/Blk wire runs up the right hand side (throttle side) a wire splices into it and goes to the plug on left hand side another splices in and goes to the two pin going to regulator, (that's a good spot to check for 12V) then it goes to the right hand plug. I had my loom apart and found the splices were well done so I wouldn't expect any problem there.

With the two large plugs apart and the two pin at regulator pulled check R/Blk wire for 12 V then we can take it from there.

I prefer to use a test lamp, something that loads the circuit up otherwise a multimeter can fool you into thinking it's OK when you have a hight resistance joint. I have a headlamp bulb with a couple of wires soldered on but a taillight or flasher bulb would be good.

[OldButNotDead]

It's really tricky troubleshooting from here but thinking about it you say " If I turn the key to ON, pressing the horn button no longer causes the horn relay to click, instead the oil and alt idiot lights come on"

I would try first to figure out why the oil and alternator lights don't come on until you press the horn button. It seems to me the horn circuit is providing the 12V that should be provided from Fuse 5, the headlight circuit.

 

Tell us a bit more about the horn relay you used, it wouldn't by any chance be a 3 wire type or you have a regular one wired with 3 wires would it?

I'm thinking that with the key off you are powering up one end of the coil from your "Hot Wire", the other end is connected to the horn button (where the horns originally connected). When you push the button the power flows from your back through the relay coil to ground through some of the other loads on Fuse F5 for example the headlight filament.

 

Actually I would be checking for a broken Red/Black wire between the large plug at right front of tank and the idiot light cluster, perhaps where it flexes with steering, I know for sure there are several spots where other wires are spliced into it.

From memory the wire runs up the right hand side (throttle side) a wire splices into it and goes to the plug on left hand side plug

Check the plug and socket for corrosion also

 

Appreciate the input Roy; was hoping you'd show up....

 

Years ago I put in a std 5-pole (30A?) automotive relay with a fused hot wire direct from the battery. Don't recall all details of how it's wired, but should know shortly.

 

I pulled the tank of this morning, and so far have checked that the ignition switch is working properly. Will print your questions and take them out to the garage. I sure hope Carl Allison accumulates some good karma every time I unroll his blessed diagram !

 

EVENING EDIT: not sure if I should be embarrassed or angry. I assumed that all these 4 (or 5) prong relays are standard the world over. I FINALLY looked at the side of the (Hella) relay I popped in to "repair" my horns. Turns out, though the terminals are numbered the same, their positions are swapped. WTF?

 

thanks for listening! I guess the upside is that I swapped out the oil breather hose while I was in there....

[Kiwi_Roy]

Years ago I put in a std 5-pole (30A?) automotive relay with a fused hot wire direct from the battery. Don't recall all details of how it's wired, but should know shortly.

I'm glad you got it sorted out.

This is the part that had me puzzled

"Now it gets weirder. If I turn the key to ON, pressing the horn button no longer causes the horn relay to click, instead the oil and alt idiot lights come on" These lights should come on when you turn the key or at least when the headlight relay powers up.

Yes, Carls drawings do make it easy but I think the electrics are still quite a challenge for most.

Try to standardize by using old relays out of the bike, that way you would have a spare and be more familiar.

I use a couple of mine for headlight relays. The 5 pin Omrons are a direct replacement for 4 or 5 pin.

Good Riding

Roy