I have a couple things going on with my 89 F150 4.9, I have no horn,wipers only work on fast and no running lights alone,but do come on with headlights.I replaced all the HL switch and wiper switch and can't even find the horn itself.I replaced the steering column an saw where the PO cut 2 wires and spliced 2 new wires that run directly to the solinoid,and the only wires I cut was to put a new stereo in. SO I'm Lost..

 

Your best bet is to get the wiring schematics for your truck and trace the wires, make sure everything is run correctly and clean all contact point and grounds.

 

Check fuses.
Just buy a new horn. The stock ones are crap anyways. Wire it to a button on the dash, they make buttons specifically for it.
Windshield wipers, check the relay.

 

I did check the fuses but I didn't think about the relays..Thanks

 

Suspect the wiring changes are your culprit, but you might also want to pull any ground wires to the chassis and scrub any corrosion on the connectorm the bolt, and the chassis. Bad grounds often cause flaky behavior like that.