ive just installed an after market dash tach and all is working, except that one signal light indicator is on also brake light and alternator light are on all go off when light switch is off any ideas are welcome thanks in advance
Brake light is suposed to light when you pull-push the emergency brake. It has a switch on the lever-pedal. Modern cars with a dual brake system (I strongly recomend upgrading to a dual brake system for safety) will also light the brake light if the piston in the sensor goes over center indicating one brake system has failed.
Alternator light is supposed to light up only when your battery discharges with the ignition on. Neither indicator light should be illiminated by the light switch. If they are affected by the light switch I would suspect someone has removed the indicator bulbs and you are seeing dash lighing shining through an open light socket hole.