2012 G29 Under power issue

[Wrm50]

I have a 2012 g29 with 6” lift and 22” tires. Everything else is stock. Replaced batteries recently, and all was fine. My kids decided to “wash” the cart for me to clean it up before hunting season. Now the cart seems to lunge when starting, run under powered when pedal is completely depressed, and lunge occasionally While driving. I did some research and tried the push test to see if the motor speed sensor was the issue and got no resistance. I removed the reverse buzzer, so I did not get any audible indications while it was rolling. Thoughts on what the issue could be? Also, there is a grey connection near the run/tow switch that is somewhat melted from a bad battery connection from the old batteries. It is not hooked up to anything, but what is it and what is its function? Thanks in advance!

[Wrm50]

So I replaced the motor speed sensor today and still no resistance. Used the tap on the end of the motor trick, and I finally got resistance while pushing the cart. Took it for a short drive and same issue with under power again. When I stopped I pushed the cart again and no resistance. Tapped on the motor again and pushed again and got resistance. So, obviously the motor/brushes are the issue. Is it worth my time to take the motor apart and blow it out/change brushes or would I be better off to change the whole motor out with a d&d torque motor? I know very little about electric motors, so any guidance is appreciated!

[rstacy]

The grey port is for the IR connection. It is used to read/program the controller. I have seen a few of these that have been damaged by the battery off gassing. You don't care if you don't plan on reading dat from the controller. Just make sure that the plug damage wont allow ant of the wires to make contact.
I agree that you probably need motor brushes. Replacing the brushes is not a difficult job and much cheaper than buying a motor.

[Wrm50]

Just an update. The old motor was burned up, so I replaced it with a d&d high torque motor. The cart seems to be running fine now. Now, I’m looking at the alltrax 500 amp controller, upgraded solenoid, and 2 or 4 gauge wiring. This will be a purchase next year at some point, but any input on these upgrades? Do I need the on the fly controller? Thanks in advance!