F/R switch or Dead cell in Batteries

[Cutch78]

Hello to all, new here, so I have a 2000 Ezgo TXT electric cart, had an issue with a few weeks back with the F/R switch getting extremely hot, actually smoking a little, so I took it out and noticed wires were a little loose and tightened them back. This fixed the F/R switch from continuing to get hot. So now my son was riding it and cart just stops, no solenoid clicking or anything. Got it home and started troubleshooting and found the solenoid was burnt up and big studs were sloopy loose, ordered a new OEM solenoid and still no sound. Here is the weird thing going on, my batteries are old but they all check good on every individual battery with load tester, and 6.3volts on each battery, and I am getting 38.6 volts to the solenoid. Can anyone please answer this question...I have a test light with red led light that will light red when contacted with a power source, so I was placing my test light on each battery terminal with red light lighting up and when I got to the fourth battery my test light lights up green. Meaning a open circuit to ground per google. So does anyone think that means a dead cell all of a sudden, just like that, or I still may have an issue with my F/R switch? All suggestions will greatly appreciated.