Battery condition is extremely important. No voltage regulator can work correctly with a bad or weak battery. Always fully charge your battery before performing any charging system tests or replacing parts. If there is any doubt, have the battery load tested or replaced.
There are two possible regulators for the Polaris Ranger 500 Series 11 2004. This regulator fits models built after 8/09/02 (LR-390). For the models built before 8/09/02 (LR-35), the right part is RM30012. Always check in the 'Fits models' section and please compare to your original part before buying.

There are two possible regulators for the Polaris Sportsman 600 and Sportsman 700 2004 models. This regulator fits models built before 2/17/03. For models built between 2/17/03 and 4/05/04, the right regulator is part RM30Y14. Always check in the 'Fits models' section and please compare to your original part before buying.
Aftermarket replacement part for:
Polaris ATP 500 -- 2004
Polaris Magnum 500 HDS 4x4 -- 2003
Polaris Scrambler 500 4x4 -- 2003
Polaris Sportsman 400 -- 2003
Polaris Sportsman 400 4x4 F/C Carb -- 2004
Polaris Sportsman 500 4x4 -- 2003-2004
Polaris Sportsman 500 HO -- 2003
Polaris Sportsman 600 -- 2003-2004
Polaris Sportsman 700 Carb -- 2003-2004