12 Volt Electrical Issues

I have been trying to resolve some electrical issues with my neighbors 2005 GEM e4, with no success.

The problems began with the cart only operating in the slow speed mode. Reverse still functioned, but forward was only “slow” regardless of the forward speed switch position. After some research, it seemed likely that the throttle pedal was at fault. I temporarily, swapped in a throttle from an 07 and the cart operated at high speed right away, but the dash would flash on and off. I removed the borrowed throttle and installed a new unit for a 2005. At first, everything worked well, but quickly devolved. The cart suddenly died and would not power up. After a half hour on the side of the road, it suddenly began working properly, but then would die off every time any 12v accessory was activated (brake lights, turn signals, horn, etc). As long as nothing 12v was used, it would run. I took the dash apart and looked for shorts, chafed wires, bad connections etc. Other than a few poor crimp connections, everything looks good. As a precaution, I removed all unnecessary fuses and went for a ride. Seemed to work fine. I put it back together and was greeted with a code 11. There is nothing around the throttle pedal and the emergency brake switch works as it should. The dash would light up as it should initially, but shortly thereafter it started flashing on and off. I can also hear the built in relay, located above the fuse panel, clicking on and off. The main contactor is also not engaging. Any thoughts?