Crown Victori PP Need Electrical Help

[CVPP]

Alright, I have a 92 Crown Victoria Police Package with a 94 PP engine in it. But for some reason all of a sudden my car is acting funny. When I push on the brake or when I turn on my lights radio or heater by volts go down and my car will sometimes shut off. Now, I have had both the Alternator and the Starter checked. I put a new starter in the car and the alternator was fine. I cleaned all the grounds. So please help!!!

[syeve]

sounds like the battery, if the alternator is running properly...actually, how would the car start then...did you have any trouble starting it? has it been happening for long? If you had trouble starting it its the battery or possible a short int he wires somewhere...why do i write when I have no idea what im doing?

[CVPP]

No, I had the battery tested I had everything tested and it is pissin me off because I have no clue on what it is. It would start up but once your turn on anything electrical or push on the brake it starts to die and then finally dies. I am not sure what it is.

[12V]

it's probably somthing to do with all the shit police to their cars, ...ever looked under the dash of a cop car..Not Pretty!