oil pump went out on my daily driver cadillac. horn was working fine. sat for 3 months probably, battery and alternator died. after i fixed it and got a new battery and alternator, the high beams and horn stopped working. i got a new high beam relay switch but I can't figure out the horn problem! is there a fuse because I couldn't see any. I didn't open up the steering wheel console or mess with any of the wiring! what is going on!

I'm thinking its a wiring problem in your steering column since the horn and high beams aren't working. Do those two circuits share a common ground? Find out where the ground is located, maybe that is the problem.

well when i figured out the alternator was bad, as i was driving at night, and everything died. lights stereo, all that. After that the high beams didn't work and i was told that the high beam switch doesn't like low voltage. Does anyone know if they have a common ground and where it is???

I don't know if you solved this problem, but in earlier models there is a relay which gets sticky. If you hit your horn button you'll hear a clicking sound, that will be the relay activating. If you don't hear it, you'll most likely find the relay in the relay cluster to the right of the fuse panel, and in back of the emergency brake pedal. Off the top of my head I can't recall which relay is the horn. It may be the upper right.
Use a jump wire from your battery to the horns to test horns. If they sound, it is most likely the relay. If you find the relay, use a jumper wire to assertain that you have a completed circuit to your horns.

And I assume you've put a test light to the hi beam wiring at the light bulbs to verify voltage is present?

I had some similar problems with my 68 SDV. Mine was the wires that run to the starter over the passenger side exhaust manifold were about melted through... I redid all my wiring and haven't had a problem since... Dont know if that's the case in your story but might want to check them out. It wasn't until I got all the way under the car could I see how bad they were

I'm going to try the jumper wire today, I've been working from 11-10 all week and havn't had any time to myself! time to head to the garage thanks for the tips i'll post back soon