Horn wiring schematic - 1st. Gen 4Runner

I have a 1987 4Runner that the horn does not work in. I’ve tested the actual horn to battery and it blows, just not from the steering wheel. I’ve checked the contacts on the steering wheel that rub when turning and everything is electrically good. My 4Runner previously had an aftermarket alarm system in it and I suspect that when installed it was placed in series of the horn, then when taken out the wiring was never put back to stock.
Anyone have a wiring schematic for the horn or some good places to look where the wires may have been cut? I do see some wires under the drivers dash that have been cut, just not sure if they are horn related. Everything else works as it should.
Thanks for your time!