wiring digram and used horn

I have just bought a 1991 GMC Jimmy. The horn doesn't work, I bought one from a junkyard, but alas it did not work. I am looking for another horn to try. Also, I am needing the wiring diagram for this vehicle. Lastly, I am need of 4 rims and at least 2 tires. Can anyone help me, please?

Buy a multimeter (digital) and check for a voltage at the horn terminal. Make sure the horn has a good chassis ground.

The wiring diagram you'll find in either the Haynes or Chilton repair manuals.

Best place to go would be a scrapyard for the rims. If you want new, it'll be any automotive accessory outlet. Phone book either way. Or Ebay.