1985 RX7 GS - previous post I said dash gauges not working but later I saw too that alternator and heat hazard indicator lights were on and the turn signals weren't working.
mechanic has ruled out fuses and alternator. Any thoughts as to cause?

 

Pull your instrument cluster and check it for loose connections, and look for the ground wire, clean up its connection. The big flasher unit by the fuse box can be a problem, check the flashers power and ground wiring. My car had a wire clipped by PO to disable a warning buzzer, side effect was it killed my turn signals.