Diagnosing intermittent running issues

[Ajaysummer]

I have a 1991 Electric EZGO Marathon 36v series system (based off what I am able to deduce). I believe I have the solid state version as I don't see any resistor coils and from my understanding the coils are quite obvious. It was given to me recently and I am by no means a professional when it comes to electric vehicles. I was told that the cart would originally quit working when a bump was hit, but would go again after letting off and hitting the accelerator again. Then one day it wouldn't move at all. Solenoid was replaced (prior to me obtaining the cart) and clicks when the key is on and forward and reverse conditions are met. I was messing around with some connections yesterday and it moved a few times for me briefly (not sure which connections were the culprit because I was checking all of them for security). It would only go when I depressed the accelerator only a little at first, but then it ran beautifully for a few minutes (until I put it away it ran fine - despite hitting bumps and joyriding down the block). It did have trouble climbing even the slightest hill, but I attribute that to only having 34 volts off the batteries at the time. I charged it overnight and now nothing again. Solenoid still clicks. Fully charged I am reading 42 volts off the batteries. After disconnecting the charger and with the system turned off still I am hearing a "buzzing" noise from either the controller or potentiometer (somewhere in that area). I need some help diagnosing the issue here. I am suspecting the potentiometer vs the controller being bad or having a bad connection somewhere on that side of the solenoid. I suspect the motor is fine as it worked beautifully yesterday. I was able to find the service manual for what I believe is my cart (I don't know the model number) but it's not as helpful as the service manuals for other vehicles I have obtained (no step by step instructions for diagnosing issues). Any basic instructions on how to self diagnose/test the issue here would be wonderful and I would truly appreciate the help.

[Ajaysummer]

Just noticing there doesn’t appear to be a diode or resistor on the solenoid either.

[Ajaysummer]

Anyone out there with any advice yet? After digging a little deeper with my DVM/DMM the cart randomly started going again. I tried to take it for a spin and it died after a few feet. Coasted it back into the barn and it started working again after a few minutes. Could this be related to the missing resistor (or less likely diode)? Is the controller fried due to lack of resistor and diode? Anyone have these issues before?

By the way, batter pack voltage was normal after I came back (38v after charge), the initial 42v I was reading right after I pulled the charger must have been residual voltage from charger?

I am going to try to test the potentiometer (found some help doing this on another site) and test the controller (using simple instructions on this site involving M- terminal) in the near future, but, as I stated, I am no electrical expert here. If someone has any explanations or further troubleshooting I should try I would appreciate it. I am a little mind boggled as to why it only runs randomly, doesn't seem to be any rhyme or reason to it.

[mrtelec]

there is a switch on the cart where the charger plugs in and is connected to the white wire coming out of the connector, called a reed switch, it has a magnetic switch that keeps it from going when it is charging, if it is stuck it wont let it go. do you have a link to those tests that you mentioned