My turn signals stopped working (both sides) on my 1984 300 SD. After reading some posts here, I tested both the hazards and the horn, which, it seems, may be related to the turn signal circuit. The hazard works fine, but the horn does not work at all. Any suggestions?

As an aside, I could conceivably use hand signals to tell others when I want to turn, except the driver's side electric window will not go down (nor will one of the passenger windows). That's my next project, if I can find the right motors.

Thanks