Horn doesn't work; How to not be an idiot in 10 easy steps

[Son_Of_Dog]

Well, like most new things that I get, I've begun the disassembly of the Skunk. The horn did not work when I got the bike and we assumed it was due to the horn being filled with mud dobber nests. The steps taken for the repair are below (happy ending included):

1. Horn does not work.
   • Clear visible mud dobber nests, no sound.
   • Meter test inconclusive; voltage changes on button press, but not to the expected 12v
2. Assume problem is combination of wiring and clogged horn
   • Clean horn more thoroughly and wire directly to battery for testing
3. Horn makes weak gurgling "poot" noise
4. Begin wire chase sequence
5. Remove headlight plate and headlight, disassemble headlight casing
   • Discover wire connections in headlight casing
   • Realize that I have no idea how a Rocket is wired
6. Discover aftermarket-looking mystery box inside of headlight casing
   • Disassemble, discover that it powers an out-of-date phone charger
7. Borrow stock Thunderbird horn from @UnicornRider and @Mad Dog to test wiring
   • No sound on button press; Feel onset of regret, activate brain
8. Check fuses
   • Horn fuse is burned through; replace fuse
9. Horn makes noise
10. Acquire new horns, wire into existing horn system; Reassembly pending

See attachments for reference, new pictures pending reassembly

Skunk3

• Son_Of_Dog
• Aug 5, 2019

Mystery Box

• Son_Of_Dog
• Aug 5, 2019

Headlight Disassembled

• Son_Of_Dog
• Aug 5, 2019

 

[EasTexRIII]

makes weak gurgling "poot" noise

Quit making fun of older fellers!

 

[EasTexRIII]

7 inch led headlamp | eBay

And car horn from a junk yard

 

[idk]

Them tere fuses can get you every time.

 

[Son_Of_Dog]

I may have jumped the gun a little bit regarding taking it apart, but I know more now than I did before. Probably worth the trouble just to learn.

 

[Mad Dog]

You read voltage on a circuit with a blown fuse? I don’t think that is supposed to happen. Something else is shorting into that circuit or feedback from something going to ground when it shouldn’t?
Make sure you’ve got the meter set up right and check it again maybe.
The service manual I sent you is the same one in idk’s signature, in the back are wiring diagrams. Look and see where the horn circuit goes. If it goes through the ignition switch and still has voltage on it with the fuse out it would worry me.

 

[Son_Of_Dog]

You read voltage on a circuit with a blown fuse? I don’t think that is supposed to happen. Something else is shorting into that circuit or feedback from something going to ground when it shouldn’t?
Make sure you’ve got the meter set up right and check it again maybe.
The service manual I sent you is the same one in idk’s signature, in the back are wiring diagrams. Look and see where the horn circuit goes. If it goes through the ignition switch and still has voltage on it with the fuse out it would worry me.

It was in millivolts, which I would assume is the meter looking too hard and seeing ghosts.

 

[Rocket_Rider]

yeh, the number of times I’ve had a brown pants moment thinking I’ve buggered something electrical on a bike only to discover it’s the fuse... I’ve lost count.... now I just check fuses first... isn’t there a saying about the simplest explanation is usually right? I generally find that when the fit hits the shan the answer was staring me in the face all along ....

 

[atlsrt44]

Did you realize the horn still sounds gay even when working properly?

 

[Jag]

If it’s like the touring model I have, the positive wire is hot all the time at the horn and they are switching the negative wire.