Rep Power: 0

I have a 91 si and when i bought it the battery light was on, so i put a new alt. on The car also has an aftermarket alarm. It runs ok, until it gets up in the heat range than i'll be driving and when i put on the headlights or turn on the blinkers the tach fuel and temp gauge start doing wierd things, for example the tach and trmp gauge will move with the blinker and the fuel gauge will go past full. The radio will turn on and off also. If i go from low to high beam it will affect the gauges also. Today the battery light came on again. I think there is a short to ground somewhere but am not sure where to start the trouble shooting process. Does anyone have any suggestions and has this happened to anyone else? I appreciate any help . Thanks for your time

 
Rep Power: 812

try and trace the wiring coming from alternator. make sure the ground and power on the alternator is tight, also check the battery terminal connections.

 
Rep Power: 0

sounds like a short to power actually. if a wire's insulation were to rub through another circuit it could cause power to be transfered to the unintended circuit and cause unexplainable dash movements. installation of the alarm could have damaged the circuts with mounting screws. i suggest some exploritory surgery and follow the wires back.