If the solenoid is only engaging (closing in) because you are having to manually supply the Neg (which the controller should have supplied) and then after it closes you are not getting anything from the controller, then it has definitely failed you. And on a Regen 2 cart, you have honestly gotten more life out that controller than many have.... They take special equipment and skills to work on so its not repairable by the normal end user.
Alltrax was supposed to have released there XCT model for the Regen 2 cart that is plug & play. This would be your best alternative.
David Hicks at Revolution Golf Cars was working with them on it.
Phone: 706-431-3917 Email:
info@revolutiongolfcars.com