need help with Melex resistor

[mobilefleet]

I bought an old Melex off ebay, model 252. Have no idea what year it is, but I'm thinking it needs a new resistor set because I changed out the solenoid and ignition key switch, and the batteries seem good. They are not fully charged up but when I try to run the cart (it's jacked up with the 2 rear wheels off the ground) with the cart plugged in to the charger, the motor shaft spins slowly with the pedal to the metal and the rear wheels barely move. The motor is brand new and I know it's not that. Question is, what year is a 252? And I came across a resistor pack on ebay that says for EZ-go 1984 and older models, and looks like it could work since I know Melex is an ezgo knock off brand. Would that work? And if so, is the resistor pack just a 2 wire connection when I get it because it looks like 2 short battery cables go to it, but mine is so old and corroded I don't know how it is supposed to be wired properly. Thanks for any help