Help, Speedometer and rev counter.

[marinamad]

When i did not have voltage resistor if i turned on flasher left/rifght rev counter would pulse up and down with flasher,,
voltage resistor is just a wee white thing with a spring looking coil off wire in back it goes in + power feed to coil

[jiversteve]

Its difficult to judge electrical problems at a distance. If you are getting some sort of interaction between electrical items you are probably looking for a poor negative/earth connection somewhere that is effectively back feeding through another component, finding the easyest return path to the chassis.
Its going to be out with a circuit diagram and multimeter, checking that each components negative terminal has a good connection back to the chassis. Anything over an ohm can start causing problems.
Good luck!