The E-Z-GO golf cart has two kinds of speed controllers, the Precision Drive System (PDS) and the Drive Control System (models before 1994). If your cart is having problems running at a constant speed or is performing erratically, then you should troubleshoot the controller to find out what the problem is.
Difficulty: Moderately Challenging
Flip the maintenance switch - Both types of E-Z-GO controllers have a maintenance switch which should be flipped when servicing or troubleshooting. The switch is under the seat and should be changed to "Tow-maintenance" mode.
Reconnect the battery cable - Disconnect the black battery cable (negative) from the battery, open the cover to the speed controller and then reconnect the negative battery cable.
Inspect wires and check voltage - Inspect all wires to ensure that they are attached and well connected, there are no breaks, corrosion or interference with the wires. Take the reading of the battery voltage by connecting the positive and negative probes to the battery. Write down the voltage reading.
Test the solenoid - Place the positive probe on the solenoid post that is closest to the battery. The reading should be equal to battery's voltage. If not, there is a wiring issue in the solenoid.
Connect the positive probe to the other post and take a reading. If the voltage is not at least three volts less than the voltage reading for the battery, the resistor must be replaced.
If you have a volt reading equal to the battery volts, the solenoid is the issue.
Check the power output from the controller - Connect the negative probe to the controller's M terminal and positive probe to the B+ terminal. Press the accelerator and watch to see if the voltage increases. It should increase from a reading of 0 to the full voltage of the battery. If the motor is not turning, the problem may be in the directional switch or motor. If there is no voltage, the controller is bad and must be replaced.
Tips & Warnings
Always use caution when handling electrical components and testing voltage readings.