Rickochet Steve, just another tidbit as you are poking around, electric carts are (or should be) grounded back to the battery pack, not the frame.
Yes, all is grounded properly - the cart operates fine - just not lights or horn.
Poked around today - more facts, but not being an electrical dude, I'm not sure what they mean.
The small red wire from the 1st (or last) battery goes down to a fuse box that holds three 20 amp fuses. All fuses look to be intact (not blown). I am guessing this circuitry is for the accessories (lights, horn, brake lights) based on the small colored wires coming out of the fuse box.
I pulled the dash assy out (holds the on/off key switch and light switch). Nothing looks shorted, burned or unplugged.
I measured the voltage across the light switch terminals. When the switch OFF, I get 14 volts. When the switch is ON, I get nothing. Izzat significant?
When I put the voltmeter terminals across the horn switch, I get nothing.
When I was reattaching the horn switch, I heard a clicking sound coming from the dashboard assy, It wasn't clear to me where the clicking was coming from, but it was def the dash. I can move the horn button back and forth (sideways) and make the clicking sound happen - it def sounds like an electrical contact opening and closing.
Could I have a bad light switch? If so, could that keep the horn from functioning? How about vice versa?
I could troubleshoot by replacing both switches - might be an inexpensive way to try.