A compressor comprising: a housing; a first scroll member supported within said housing and including a first end plate, a first spiral wrap extending from a first side of said first end plate, a first chamber located on a second side of said first end plate having first and second passages (150,154) in communication therewith, a second chamber located on said second side of said first end plate having third and fourth passages (158,162) in communication therewith, said first and third passages (150,158) being in communication with a first pressure source and said second and fourth passages (154,162) being selectively in communication with a second pressure source, a first aperture extending through said first end plate and in communication with said first chamber, and a second aperture extending through said first end plate and in communication with said second chamber; a second scroll member supported within said housing and including a second end plate having a second spiral wrap extending therefrom and meshingly engaged with said first spiral wrap to form a series of pockets, said first aperture being in communication with a first of said pockets operating at a first pressure to provide communication between said first pocket and said first chamber and said second aperture being in communication with a second of said pockets different from said first pocket and operating at a second pressure to provide communication between said second pocket and said second chamber; and a compressor output adjustment assembly including first and second pistons (192,198), said first piston located in said first chamber and displaceable between first and second positions and said second piston located in said second chamber and displaceable between first and second positions, said first piston isolating said first aperture from communication with said first passage when in its second position and said second piston isolating said second aperture from communication with said third passage when in its second position. a housing; a first scroll member supported within said housing and including a first end plate, a first spiral wrap extending from a first side of said first end plate, a first chamber located on a second side of said first end plate having first and second passages (150,154) in communication therewith, a second chamber located on said second side of said first end plate having third and fourth passages (158,162) in communication therewith, said first and third passages (150,158) being in communication with a first pressure source and said second and fourth passages (154,162) being selectively in communication with a second pressure source, a first aperture extending through said first end plate and in communication with said first chamber, and a second aperture extending through said first end plate and in communication with said second chamber; a second scroll member supported within said housing and including a second end plate having a second spiral wrap extending therefrom and meshingly engaged with said first spiral wrap to form a series of pockets, said first aperture being in communication with a first of said pockets operating at a first pressure to provide communication between said first pocket and said first chamber and said second aperture being in communication with a second of said pockets different from said first pocket and operating at a second pressure to provide communication between said second pocket and said second chamber; and a compressor output adjustment assembly including first and second pistons (192,198), said first piston located in said first chamber and displaceable between first and second positions and said second piston located in said second chamber and displaceable between first and second positions, said first piston isolating said first aperture from communication with said first passage when in its second position and said second piston isolating said second aperture from communication with said third passage when in its second position.