2008 wr250r horn not working

Trying to get the bike ready for rego inspection. This is the last piece of the puzzle.

Aftermarket indicators were poorly wired in, fixed them.
Horn switch works, and creates an open circuit with multimeter at the horn itself. The wiring at the horn is earthed, as is one side of the switch (black wire)

BUT from reading the wiring diagram the horn should have 12v and the pink wire on the switch have 12v...? This isn't there.

Any ideas where the connection for the horn is in the loom, or any obvious spots it could of failed at? I know I could run a sneaky power to get it working, but would rather fix it properly so I'm not chasing out why my electrical system fried itself in the middle of nowhere.

I'm out of ideas.

I just took a look at the wiring diagram and it's a fairly basic circuit.

The brown +12v wire to the horn is powered via the ignition switch and shares the 10 amp ignition fuse.

The horn is switched on the earth ground side of the circuit. The pink wire is the earth ground wire between the horn and the switch. The black wire connects the horn switch to actual earth ground when pushed.

With the ignition switch on you should have +12v at the brown wire at the horn. Otherwise the 10 amp fused ignition circuit would be open and the bike wouldn't run.

With +12v on the brown wire the horn should work when you connect the earth ground (pink wire) side to ground. I just verified this on my bike with a jumper wire.

My guess is corrosion in the electrical connectors at either the horn or the horn switch.

My horn didn't work when I bought my bike. I took the switch assembly apart, cleaned out the switches with Q-tips and WD-40 and voila the horn worked again. It was pretty filthy inside and everything was coated in dirt.

Pay close attention to how it comes apart. I thought I did, but then when I went to put it back together I had some trouble with the order things went back in. It was fine, it just took a few more minutes to reassemble.

@wwguy thanks! The wiring diagram I have, has the horn coming off the signals.

Your 'brown wire' reference which I was told was a running light and nothing to worry about, save it for switched power down the track... was my missing 12v!

Connected it in and now I have a horn.

If it wasn't for the inspection, you could just use your finger. Sorry had too!

I'm glad it worked!