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Troubleshooting Harley Davidson Golf Carts DEC 1966 to 1968

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Troubleshooting Harley Davidson Golf Carts DEC 1966 to 1968

Last Updated on March 5, 2024 by Chuck Wilson

The DEC differs from the DE model with the addition of headlights, taillights, and a  horn. The High Range/Low Range capability was available in the 1966 through 1968 DEC.

The Harley Davidson Golf Cart was manufactured from 1963 through 1982 and came in models DE, DEC, DEF, DE-3, and DE-4

Troubleshooting Harley Davidson Golf Carts DEC

Troubleshooting Harley Davidson Golf Carts DEC can be a complex task, but it’s necessary for maintaining the performance and longevity of the vehicle. This process involves diagnosing the issues, which could range from engine problems to electrical system malfunctions.

1966-67 Model DEC Heavy Cable Diagram

1966-67 Model DEC 16 Gauge Cable Diagram

The above diagram is correct for the 1966  and 1967 model DEC. The 1966 model changed from a belt drive to a direct drive axle requiring the motor to rotate in the opposite direction from the prior models. The key switch connections changed so that REV becomes FWD for solenoids A and B and FWD becomes REV for solenoids C and D.

1966-67 Model DEC Charging

  • Key switch – Off
  • Speed Switch – at resting stop
  • Solenoid “A” Open – Voltage not applied to small terminals
  • Solenoid “B” Open – Voltage not applied to small terminals
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Solenoid “H” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Voltage to Motor – None
  • Voltage across A1 and A2 – None
  • Micro Switch – Open

1966-67 Model DEC First Speed High Range

High Range – 36 volts – 6 batteries in series

  • Key Switch – FWD
  • Speed Switch – Moved off of resting stop – Not in contact with terminal 8 yet
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between Large terminals – Voltage redirected through full resistor
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Solenoid “H” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC Second Speed High Range

High Range – 36 volts – 6 batteries in series

  • Key switch – FWD
  • Speed Switch – at Terminal 8
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between Large terminals
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Energized – Continuity between large terminals – Voltage redirected through middle tap on resistor
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Solenoid “H” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC Third Speed High Range

High Range – 36 volts – 6 batteries in series

  • Key Switch – FWD
  • Speed Switch – at Teminal 11
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between large terminals
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Energized – Continuity between large terminals – Voltage bypassing resistor
  • Solenoid “G” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Solenoid “H” Open – Voltage not applied to small terminals – Lower contacts closed and bridging
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC First Speed Low Range

Low Range – 18 volts – 2 sets of batteries in parallel

  • Key Switch – FWD
  • Speed Switch – Moved off of resting stop – Not in contact with terminal 8 yet
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between Large terminals – Voltage redirected through full resistor
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Solenoid “H” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC Second Speed Low Range

Low Range – 18 volts – 2 sets of batteries in parallel

  • Key switch – FWD
  • Speed Switch – at Terminal 8
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between Large terminals
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Energized – Continuity between large terminals – Voltage redirected through middle tap on resistor
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Solenoid “H” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC Third Speed Low Range

Low Range – 18 volts – 2 sets of batteries in parallel

  • Key Switch – FWD
  • Speed Switch – at Teminal 11
  • Solenoid “A” Energized – Continuity between large terminals
  • Solenoid “B” Energized – Continuity between large terminals
  • Solenoid “C” Open – Voltage not applied to small terminals
  • Solenoid “D” Open – Voltage not applied to small terminals
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Energized – Continuity between large terminals – Voltage bypassing resistor
  • Solenoid “G” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Solenoid “H” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1966-67 Model DEC Reverse (First Speed Low Range Shown Only)

Low Range – 18 volts – 2 sets of batteries in parallel

  • Key switch – REV
  • Speed Switch – at Terminal 8
  • Solenoid “A” Open – Voltage not applied to small terminals
  • Solenoid “B” Open – Voltage not applied to small terminals
  • Solenoid “C” Energized – Continuity between large terminals – S1 and S2 now reversed in polarity
  • Solenoid “D” Energized – Continuity between large terminals – Voltage redirected through full resistor
  • Solenoid “E” Open – Voltage not applied to small terminals
  • Solenoid “F” Open – Voltage not applied to small terminals
  • Solenoid “G” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Solenoid “H” Energized – Continuity between upper large terminals placing batteries in parallel- Lower contacts open
  • Voltage to Motor – Present
  • Voltage across A1 and A2 – Present
  • Micro Switch – Closed

1968 Model DEC 16 Gauge Cable Diagram

1968 Model DEC Heavy Cable Diagram

Differences in the 1966-67 Heavy Cable Diagram and the 1968 Heavy Cable Diagram is the addition of two (2) Circuit Breakers (Item 32), Motor Terminal S1 and S2 Reverse Connections.

Solenoid Arrangement For Harley Davidson Golf Cart DE 1966-68

Numbering Key for 1966 -1968 Diagrams

  1. Key Switch – 3 wires (Green, Blue, Yellow) For terminals 2, 3, and  4
  2. Key Switch Terminal – Green wire to Speed Switch Connection 9
  3. Key Switch Terminal – Blue wire to Speed Switch Connection 10
  4. Key Switch Terminal – Yellow wire to Micro Switch 13, Yellow wire to Speed Selector Switch 25
  5. Speed Switch (Contains Terminals 6, 7, 8, 9, 10, 11, and 12)
  6. Speed Switch Terminal – White wire to Terminal 12 on Switch Arm, Red wire to Micro Switch, Red wire to Solenoid Terminal G5 – 3 wires
  7. Speed Switch Terminal – White wire to 12v Tap  on battery, White wire to Solenoid Terminal C2
  8. Speed Switch Terminal – Yellow wire to Solenoid Terminal E3
  9. Speed Switch Terminal – Green wire to Key Switch Terminal 2 and Green wire to Solenoid Terminal A3
  10. Speed Switch Terminal – Blue wire to Key Switch Terminal 3 and Blue wire to Solenoid Terminal C3
  11. Speed Switch Terminal – Red wire to Solenoid Terminal F3
  12. Speed Switch Arm Terminal – White wire jumper to Speed Switch Terminal 6
  13. Micro Switch – Yellow wire to Key Switch Terminal 4 and Red wire to Speed Switch Terminal 6
  14. Charger Connection Plug – Negative Terminal 1 Black wire to Speed Switch Terminal E4 and Positive Terminal 2 Red wire to Solenoid Terminal G1
  15. Motor – 5 wires
    A1 – Black wire to Solenoid Terminal G1, Black wire to Right Rear Battery Positive Terminal
    A2 – Black wire to Solenoid Terminal C1
    S1 – Black Wire to Solenoid Terminal D1 (or to Solenoid Terminal B1 1968 Model only)
    S2 – Black Wire to Solenoid Terminal B1 (or to Solenoid Terminal D1 1968 Model only)
  16. Resistor – 3 wires
    Terminal .1 – Black wire to Solenoid Terminal E1
    Terminal .3 – Black wire to Solenoid Terminal F4
    Unmarked Terminal –  Black wire to Solenoid Terminal B4
  17. Solenoids A, B, C, D, E, F, G, and H
    Solenoid  A -Located top left (front of the cart)
    A1 – Copper strap to Solenoid Terminal C1
    A2 – White wire to  Solenoid Terminal C2 and White wire to Solenoid Terminal D2
    A3 -Green wire to Speed Switch Terminal 9 and  Green wire to Solenoid Terminal B3
    A4 – Copper Strap to Solenoid  Terminal D1Solenoid B – Located bottom center
    B1 – Copper Strap to Solenoid Terminal C4, Black wire to Motor Terminal S2 (or Motor Terminal S1 1968 Model only)
    B2 – White wire to Solenoid Terminal D2
    B3 – Green wire to Solenoid Terminal A3
    B4 – Copper Strap to Solenoid  Terminal D4, Black wire to unmarked Resistor TerminalSolenoid C – Located bottom Left (front of the cart)
    C1 – Copper Strap to Solenoid Terminal A1, Black wire to Motor Terminal A2
    C2 – White wire to Solenoid Terminal A2,  White wire to Speed Switch Terminal 7
    C3 – Blue wire to Solenoid Terminal D3, Blue wire to Speed Switch Terminal 10
    C4 – Copper Strap to Solenoid Terminal B1Solenoid D – Located top center
    D1 – Copper Strap to A4, Black wire to Motor Terminal S1 (or Motor Terminal S@ 1968 Model only)
    D2 – White wire to Solenoid Terminal F2, White wire to Solenoid Terminal B2, White wire to Solenoid Terminal A2
    D3 – Blue wire to Solenoid Terminal C3
    D4 – Copper Strap to Solenoid Terminal F1, Copper Strap to Solenoid Terminal B4Solenoid E – Located bottom right (rear of the cart)
    E1 – Black wire to Resistor Terminal .1
    E2 – White wire to Solenoid Terminal F2
    E3 – Yellow wire to Speed Switch Terminal 8
    E4 – Copper Strap to Solenoid Terminal F4, Black wire to Charger Negative Terminal Solenoid F – Located top right (rear of the cart)
    F1 – Copper Strap to Solenoid Terminal D4
    F2 – White wire to Solenoid Terminal E2, White wire to Solenoid Terminal D2
    F3 – Red wire to Speed Switch Terminal 11
    F4 – Copper Strap to Solenoid  Terminal E4, Black wire to Solenoid Terminal H1, Black wire to .3 Resistor Terminal,  Black Wire to Speed Switch Terminal 6 Solenoid G – Left side of  Solenoid Plate
    G1 – Red wire to Pin 1 of Charger Plug, Black wire to Motor Terminal A1
    G2 – White wire to Solenoid Terminal H2
    G3 – Black wire to Solenoid Terminal H3, Black wire to Speed Selector Switch
    G4 – Red wire to Light Switch, Black wire to Left Front Battery Positive Terminal (or to Circuit Breaker #1 Terminal 1 1968 Model only), Black wire to Solenoid Terminal H5
    G5 – Black wire to Solenoid Terminal H4, Red wire to Speed Switch Terminal 11
    G6 – Black wire to Solenoid Terminal H6Solenoid H (Speed Control Solenoid) – Left Side of Solenoid Plate
    H1 – Black wire to Solenoid Terminal  F4, Black wire to Front Right Battery Negative Terminal 20
    H2 – White wire to Solenoid Terminal G2, White wire to Solenoid Terminal F2
    H3 – Black wire to Solenoid Terminal G3
    H4 – Black wire to Solenoid Terminal G5, Black wire to Rear Left Battery Negative Terminal (or to Circuit Breaker #2 Terminal 1 1968 Model only)
    H5 – Black wire to Solenoid Terminal G4
    H6 – Black wire to Solenoid Terminal G6 
  18. Front Batteries (6 6-volt in series to give a  total of 36-volts. Includes tap for 12 or 18-volts for the solenoid circuit. (see the dashed area at front batteries)
  19.  Center Rear Battery Positive Terminal 12v Tap, White wire to Speed Switch Terminal 7
  20. Right Front Battery Negative Terminal – Black wire to Solenoid Terminal H1
  21. Right Rear Battery Positive Terminal – 18v Tap, Black wire to Motor Terminal A1
  22.  Left Terminal Board – Green wire to Right Terminal Board 23, Green wire to Light Switch 29, Red wire to Left Tail Light
  23. Right Terminal Board – Green wire to Right Terminal Board 23, Green wire to Right Taillight, Green wire to Left Tail Light, Red wire to Right Tail Light 
  24. Tail Light – Green wire to Terminal board 23, Red wire to Terminal Board 23 
  25. Speed Selector Switch – Black wire to Solenoid Termina G3, Yellow wire to Key Switch Terminal 4
  26. Fuse – White wire to Right Front Battery Positive Terminal, wire to Solenoid Plate Screw 27
  27. Solenoid Plate Screw – wire to Fuse 26
  28. Headlight – White wire to Ground Bolt 32, Blue Wire to Light Switch 29
  29.  Light Switch – Blue wire to Headlight 28, Red wire to Solenoid Termina G4, Green wire  to Left Terminal Board 22, Yellow wire to Horn Button 31
  30. Horn – Yellow Wire to Horn Button 31
  31. Horn Button – Yellow wire to Light Switch, Yellow wire to Horn 30
  32. Circuit Breakers (2) (1968 Model DEC only) G5

1966 Through 1968 Models DE and DEC Troubleshooting Chart

SymptomPossible CauseRemedy
Batteries Run Down Rapidly
Batteries not charging fullyBad BatteryTest battery cells
Low Electrolyte LevelRefill cells with electrolyte
Bad Charging CircuitInspect terminals and connections for looseness and corrosion
Bad ChargerUse multimeter and test output voltage
Battery Drain other than useCorrosionInspect battery and speed switch contacts and clean where needed
Loose ConnectionsTighten all terminals and connections
Shorts in the CircuitCheck for frayed wires touching other terminals or debris shorting contacts
Faulty MotorGo through the motor testing procedures
Drag or ResistanceBrakes tightAdjust brakes
Low Tire PressureFill tires to recommended pressure
Wheel Bearings DraggingLubricate wheel bearings or replace if bad
Incorrect Drive Belt Tension (63-65)Adjust belt tension
Differential DraggingCheck lubrication on differential and chassis
OverloadingVerify carts carrying capacity is not exceeded
Driving with foot on the brakeDon’t…this will wear out the brakes prematurely as well.
Slipping Drive Belt (63-65)Drive Belt Out of AdjustmentAdjust belt tension
Cart Will Not Operate Forward or Reverse
Batteries DischargedCheck if charger is operating properly and charge batteries
Speed Switch Failure or Linkage disconnectedCheck the operation of the foot pedal moving the switch arm and test speed switch
Key Switch BadUse continuity tester and replace if faulty
Solenoids inoperativeListen for solenoid clicks, and if no sound check wiring to terminals. Check solenoids with testing procedure.
Micro Switch inoperableUse multimeter to test micro switch operation
Drive Belt Not EngagedAdjust belt tension
Motor FaultCheck brushes and armature, run motor test procedure
Corroded Battery TerminalsCheck and clean battery posts and connections
Faulty Wiring CircuitUsing the wiring diagram for your model, trace out and correct any loose or broken connections
Car Operates Forward, Not in Reverse
Reverse Solenoids C and/or D InoperableUse testing procedure on solenoids C and D
Forward Solenoids A and/or B staying ClosedUse testing procedure on solenoids A and B
Wiring Broken or DefectiveUsing the wiring guide, test wiring to electrical components
Bad Key SwitchUsing a continuity tester, perform continuity test on key switch terminals
Car Operates in Reverse, Not in Forward
Forward Solenoids A and/or B InoperableUse testing procedure on solenoids A and B
Reverse Solenoids C and/or D staying closedUse testing procedure on solenoids C and D
Wiring Broken or DefectiveUsing the wiring guide, test wiring to electrical components
Bad Key SwitchUsing a continuity tester, perform continuity test on key switch terminals
Car Leaps or Jerks
Solenoids Sticking or HangingUse testing procedure on solenoid
Faulty ResistorCheck resistor for breaks and check taps and connections
Loose or Corroded ConnectionsClean and tighten connections
Cart Only Runs in First Speed
Second Speed Solenoid E
and Third Speed Solenoid F Faulty
Use testing procedure on solenoid
Faulty WiringCheck connections and continuity from speed switch to solenoids
Cart Runs in First and Third Speed, Not in Second Speed
Solenoid E FaultyUse testing procedure on solenoid
Faulty WiringCheck connections and continuity from speed switch to solenoids
Cart Runs in First and Second Speeds, Not in Third Speed
Solenoid F FaultyUse testing procedure on solenoid
Contacts on Speed Switch and on Third Speed not making a good contact Check and clean contacts on speed switch
Faulty WiringCheck for open circuit, shorts, or loose connections
Cart Will Run in Second and Third Speed, Not in First
Resistor open between .1 and .3 terminalsCheck continuity on resistor and connections
Faulty WiringCheck connections and continuity from speed switch to solenoids
Cart Will Not Run in First or Second Speeds, Only Third
.1 Ohm Section of Resistor between .1 and unmarked terminals open or both sections openUse continuity tester on resistor terminals
Faulty WiringCheck continuity from resistor common terminal to solenoid
Cart Runs in First Speed Then Jumps to Third Speed
Faulty WiringCheck continuity of red and yellow wires from speed switch to solenoids
Solenoid E FaultyUse testing procedure on solenoid
Cart Goes to Third Speed Immediately When Pedal is Pressed
Third Speed Solenoid F Stuck ClosedUse testing procedure on solenoid
Faulty WiringCheck wiring continuity fo blue and red wires from speed switch to solenoids
Cart Goes to Second Speed Immediately When Pedal is Pressed, Third Speed Normal
Second Speed Solenoid E Stuck ClosedUse testing procedure on solenoid
Faulty WiringCheck wiring continuity from speed switch to solenoids
Cart Starts Forward When Key Switches On
Speed Switch StuckCheck speed switch
Cart Does Not Stop With Key On
Speed Switch Arm Not Returning to Off PositionCheck speed switch, return spring and linkage
Cart Does Not Stop With Key Off
Key Switch Faulty or ShortedInspect key switch and test with continuity tester
Cart operates normally in high range, with no speed difference in low rangeCheck Speed Range Switch connections
Cart operates normally in low range, with no speed difference in high rangeCheck Speed Range Switch connections Check Speed Range Solenoids G and H
Cart operates normally in high range, does not operate in low range, OR Cart operates normally in low range, does not operate in high rangeCheck Speed Range Solenoids G and H
Front 3 batteries run down before the back rowCheck Speed Range Solenoid H
Back row of 3 batteries runs down long before the front rowCheck Speed Range Solenoid G

Many replacement parts can be found at Vintage Golf Cart Parts.

Other Years and Models for The Harley Davidson Golf Cart

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