Re: Turn signals
What are the back signals doing when both the front signals light up solid like that?
The horn coming on when you turn the wheel... sounds like something funny is going on in the steering column with the horn button contacts. If so there might also be issues with the signal switch/canceling mechanism.
First rule in electrical troubleshooting... check all your grounds. if the taillight bulb sockets are loose in the housing, the metal tabs that hold them in and provide grounding might not be making good contact with the housing, you can try bending the tabs so they hold the socket tighter against the taillight housing. The front signals have ground wires coming off them. you can connect one lead of a multimeter or test light to the positive terminal of your battery and the other lead to the terminal at the end of the signal ground wire. If you show ~12V or a lit up test light, ground is good. If not, touch that lead to some exposed metal near it, if you show a good ground, you've isolated the grounding issue to that signal's ground wire. A star washer under the terminal can help cut through the paint/crud and get good metal contact.
Another quick thing to try is swapping the hazard and turn signal relays next time your lights are doing funny things and see if that fixes the problem.
when i get home tonight i'll pull out the wiring diagram and do some head scratching. Good luck.