My 86 Lebaron just did the same thing today and hitting the dashboard made the signals start working again. I think it's my radio wiring shorting out something. Also try turning the hazards on and off to see if the signals start working...Thank you so much, I'm so friggen nervous having to do this move. Very hard for me to concentrate right now.
I also have a rear-mounted battery that leads to a nest of wires under the hood, however, I did not find any broken fuses under the hood. (There are two attached to relays)
All of this happened after I shorted out the passenger side socket using a probe... sparks flew, then I no longer had the driver's side brake like or signal anymore.