Mercury Marquis Battery Replace/Remove

When I Start The Car Everything Seems To Work Fine But When I Push The Gas Pedal The Temperature Control, Turn Signals And Interior Lights...

Everthing Works ,radio Dosen't And Car Want Start, Put New Battery In Change Neg Wire Post Still Same Problem Im Being Told That All Is A...

Replaced Starter Solenoid And Now I Have All The Wires Messed Up. I Really Need To Know What Other Wires Go Connected To Battery Terminals...

If I Install A Battery Smaller Than The One That I Supposed To Use In My 1987 Mecury Grand Marquis, What Kind Of Problem(s) (if Any) Would I...