This is a basic checklist if your vehicle will not operate.
First you will want to check the controller flashes. The green light should be constantly green if the vehicle is is operating. If not it will throw a flash / blink. By counting the blinks on the system indicator light located on the dash or on the blue Mill Pak controller, it will give you an idea to where to look first.
Check Fuses: Locate the 1 amp fuse in the main harness to see if it's blown. Replace 1 amp fuse. If it burns out again, check all the main harness for fraying, corrosion, or damage.
Charger Interlock: The interlock is the Green wire coming out of the charger harness. When not connected to AC power, this wire should have main battery voltage. When supplied with AC power there should be 0 volts at this wire.
Speed Encoder / Sensor: Located on the rear of only a Heavy Duty DC Motor "Blue" and the top of an AC motor "Black". A golf cart motor speed sensor is, in simplest terms, a device that detects or reads the rpm of the motor and transmits this information to the speed controller to control various motor functions. A golf cart motor speed sensor can be mechanical, electrical, or magnetic. We will discuss several different types, how they operate, why they are needed, and symptoms when they fail. This can also pertain to the speed of the vehicle. "Overdrive" If this is damaged in anyway the speed of the vehicle will cut in half.
Seat Switch: The seat switch is located under the driver seat cushion if so equipped. There will be two black wires coming out of the main harness connected to the wires coming from the seat. Check to see if they are disconnected, corroded, or damaged. If the vehicle still is not operable, use an ohm meter and verify that the switch is operable.
Parking Brake Interlock: Is wired in the same way as a the seat switch.
Battery Voltage: Be sure the battery pack is fully charged. Each battery should be around 6.5 volts
24v = Full Pack Voltage 26v
36v = Full Pack Voltage 39v
48v = Full Pack Voltage 52v
DC Motor Brushes
Located at the rear of the motor, the brushes are set in the aluminum portion of the housing. It is recommended to clean the brushes; but, if further damage or wear is found, replacing the brushes is recommended.
Check the key switch to insure you have system voltage (Battery Pack Voltage). If no voltage is detected, check the main harness for damage or corrosion. The key switch may need to be replaced.
Check main pin one voltage by disconnecting the 12 or 16 pin connector from the controller. Power the vehicle on and place your voltmeter positive probe to pin one and your negative probe to main battery negative. This should show system voltage. If no voltage is detected, check all connections for corrosion, damage or disconnections.
Water between B+ and Main Fuse on Controller
There have been instances where water has filled the gap between the B+ and the main bridge fuse, causing a short. B+ cable may need to be adjusted to widen the gap between the fuse and B+.