No Taillights

For the ligths isted, they all come through the headlights switch so proceed as noted.

For the occasional horn blowing when the steering wheel is turned, there is an electrical contact behind the steering wheel that rides on a ring in the upper part of the steering column. This grounds the horn relay to activate it when you push the horn. This contact or the contact ring are broken/messed up. You'll have to pull the steering wheel to see and inspect this; probably needs to be replaced.