1979 RX-7, Had a bad speedo, so I tried to put a Miata instrument cluster in- BAD idea. Bought a used cluster when that failed, but I blew something. Now the Tach volt meter does not kick off, so the tach pegs when the engine starts and "ADD COOLENT, GEN, OIL" lights stay lit. Tried old tach, same problem. Checked Regulator, front coil reads ~90 ohms, rear ~20 (May be bad?), swapped coils, no change. Any ideas? Thanks.

 

I know you said you checked the regulator, but when mine went out that is exactly what happened, the lights and the tach would peg.

See the Add coolent, gen, oil lights, and the volt meter circuit run through the voltage regulator. The regulator switches those lights on until there is a positive ignition signal.

What I did was convert to a Turbo II alt. and replaced the regulator with a 3 prong relay.

I would double check the regulator and check your fuses.

Matt