Diagnostic testing for Ezgo Solid State speed Control Systems. There are several drive systems. First Identify your drive system. If you have not done so - go to the speed controller main page for flow chart identification. 

Testing of the EZGO ELECTRONIC SPEED CONTROL -
SERIES Drive system.

ALWAYS DISCONNECT THE NEGATIVE BATTERY CABLE BEFORE REMOVING CONTROLLER COVER. RE-CONNECT CABLE AFTER COVER IS REMOVED.

These tests are to be conducted after making sure all wires and cable connections are clean and tight.

Battery pack MUST read  36v to 38v

PLACE THE REAR OF THE CART SECURELY ON JACK STANDS FOR SAFETY

Connect (-) probe of meter on Battery Pack main Negative (-) post. (This probe will on the post for the rest of the testing procedures) Connect (+) probe to the Battery Pack Positive (+) battery post. (This reading is the Battery pack voltage and is often referred to as pack voltage.

Key switch ON, gear selector in FORWARD, Place the (+) probe on the battery side of the solenoid's large post (If the reading is below battery voltage, check cable connections between solenoid and Main (+).

Place the (+) probe to the controller side of the solenoid's large post. With the resistor in place the reading should be 0.1 to 3 volts less than battery voltage. If the reading is more than 3 volts less the battery voltage, the resistor is faulty. If the voltage is the same as the battery voltage with the resistor disconnected the solenoid contacts are welded, replace the solenoid.

Solenoid test is done with the resistor removed from one large terminal. You should always have pack voltage (+) on the side connected to the batteries. When the small terminals have (+) and (-) to them the solenoid should CLICK and pack voltage should be present at both large terminals.  If no, the solenoid has failed. If (+) and (-) are not present at the small terminals when the pedal is pressed, a problem exists within the solenoid activation circuit. This circuit consists of a series of switches and is easily traced using the solenoid activation circuit diagrams available on the forum. The switches are activated in this order: Reed switch – F&R micro switch(ms) – key switch – Foot or pedal box switch. All of these switches must work before the (+) side of the solenoid activation is delivered to one of the small posts (red wire)

Most of the conversations here assume a certain level of experience with DC electric exists.
When I say check to see that positive and negative exist at the small terminals. I mean that there should be 36 V positive at the small terminal with yellow wire when you press the gas pedal with the key on and cart in gear. 
This can be checked with your voltmeter by putting the black test lead on the battery pack main negative and the red test lead on the small posts with the yellow wire.
And I mean that there should be 36 V negative at the small terminal with the blue or black wire at the same time. 
This can be checked with your voltmeter by putting the black test lead on the battery main positive in the red test lead on the small posts with the blue or black wire.
This can Also be tested by putting a test lead on each small terminal and pressing the gas pedal.The meter should read 36 V when the gas is pressed. 

If this voltage does exist when the gas pedal is pressed then the solenoid should click and engage. 
If this voltage does not exist when the pedal is pressed then you have a problem in the solenoid activation circuit. This circuit begins at a battery source go through the key switch the foot pedal switch and culminates at the solenoid.

I hope this helps
 
ITS - INDUCTIVE THROTTLE SENSOR

There are three parts to the system.

1. a voltage source from the controller 

2. a plunger and coil in the pedal box under the floor mat

3. a throttle position translator in the controller.

 

Basically, when you press down on the pedal, a metal rod is inserted into the sensor coil in the pedal box, changing the inductance of the coil, which reduces the voltage signal sent through it. This varying voltage signal tells the controller how much current the driver wants passed to the motor. Got it?  Good.

Since the controller provides this signal different controls will show different voltages.

And there are different values for different drive systems with the Curtis control.

With meter neg. probe on the B- terminal, use the positive lead to probe the white wire in the controller main  molex connector.

Curtis OEM control signal range for :

Series & DCS carts should read 0.4 - 0.6 through 1.5 - 1.7 volts

PDS carts should read 1.0v - 2.7v  (+/- 0.5v)


At Pin-1 (White wire), with pedal just pushed until the solenoid clicks should give the low end reading shown above. 
With pedal on floor, it should give the high end reading shown above.  These readings are true for the Curtis control.


The Alltrax control uses a higher voltage.

The throttle signal should start at 10 V and go down to 6 V.

If the signal is out of range the controller will not work and the ITS sensor must be replaced.
 

 

CHECKING CONTROLLER INPUT

Connect (-) probe to B- terminal.     Connect (+) probe to B+ terminal.

The reading should indicate approx. 0 volts
with the resistor REMOVED and the pedal not pressed in the last 15-30 minutes. 


CHECKING CONTROLLER OUTPUT


Slowly depress accelerator pedal until the solenoid engages. Watch the voltmeter.
The reading should show the battery pack voltage. Now slowly depress the pedal and watch the reading, it should go down to nearly 0 volts.  


​If the voltage starts at full pack and goes down near zero when the pedal is depressed and the motor is not responding  then the problem lies in the high amperage side of the drive circuit. Check the cable connections, the forward and reverse switch, and the motor.




Voltmeter testing  from M- to B+ (with F/R in F). The voltage should go from Zero when solenoid clicks to full pack voltage when pedal is on floor.

The voltage between M- and B+ with pedal down should match the voltage between the B- and B+ terminals on the controller with the pedal down.

                                                                             
If those two voltage don't match, either the controller isn't being told to open up fully (throttle issue) or the controller isn't doing what it is being told to do. (Bad controller)

 

If the test are good for the solenoid and controller operation, and the cart does not go, the problem may be in the forward and reverse switch (F&R) or the motor. Be certain that the battery pack voltage is not dropping dramatically when you try to go - this may indicate one or more bad batteries which may prohibit the cart from running. Give each cable end a pull & twist test. Some cable may be ready to come off.

 

FORWARD & REVERSE SWITCH aka F&R 
The forward and reverse switch is a simple Rotary device. Four contacts are stationary in the switch housing. And four contacts are on a rotating center cam. This configuration allows for three configurations; forward, neutral, and reverse. Contact is maintained by spring tension and friction.
You can test for continuity between parallel pairs of stationary lugs in forward and reverse position. However, the Ω test will not guarantee that the contact is good enough to withstand high amperage. It is possible to have a positive continuity test that will not hold up to actual use. A visual inspection is best. If all of the four studs are not identical in color, one or more may have gotten hot. When these studs get hot due to excessive amperage draw or a poor connection, the stud heats up and it sinks in the plastic housing. This compromises the contact with the lug in the rotating cam. If a stud has sunk or changed angle so it appears to lean then the complete switch must be replaced.
Remove the center pivot shaft 9/16 nut from the backside of the F&R to remove the shaft and switch cam for inspection.


Rocker switch test
The rocker switch F&R on Sepex carts  has power in on the center pin and power out on 1 of the 2 outer pins when each direction is selected. A simple voltage check will verify operation.

MOTOR UNWANTED CONTINUITY TEST

The following tests can assist in troubleshooting.

Disconnect all wires to the motor and label them

Make sure none of the terminals are grounded to the motor or cart

With your meters set on Ω ohms, you should have continuity present between F1 and F2, and between A1 and A2 but NOT between any A and any F Terminal.

If any of these tests fail, the motor will not operate correctly and should be repaired or replaced.

_________________________          ______________________________

ELECTRONIC SPEED CONTROL - DCS

DCS: Pin-1 (white wire) 0.4V to 0.6V pedal up and 1.50V to 1.75V pedal down.

PDS: J4 Pin-3 (black wire) should be 0.7V to 1.3V when solenoid clicks and 2.5V to 3.3V when pedal is on floor.

ALWAYS DISCONNECT NEGATIVE BATTERY CABLE BEFORE REMOVING CONTROLLER COVER. RE-CONNECT CABLE AFTER COVER IS REMOVED.

These test are to be conducted after making sure all wires and connections are clean and tight.

JACK UP REAR WHEELS or otherwise secure the rear end up off of the ground.

Connect (-) probe of meter on Battery Pack Negative (-) post.

Connect (+) probe to the Battery Pack Positive (+) post. (This reading is the Battery Voltage)

Connect (+) probe to the battery side of the solenoid's large stud.

The same voltage should be present. If not, inspect all solenoid and battery cables.

DISCONNECT battery bl(+) wire and unplug the "Run,Tow/Maintenance switch.

Perform a continuity test on wires 1 and 2, 3 and 4 TO THE CONTROLLER

Turn the key switch ON and place the gear selector in Forward.

Connect (-) probe of meter to Battery Pack Negative (-) post. (This probe will remain on the post for the rest of the testing procedures)

Place the (+) probe on the battery side of the solenoid's large post (If the reading is below battery voltage, check all wiring and terminals).

Place the (+) probe to the controller side of the solenoid's large post. The reading should be 0.1 to 3 volts less than battery voltage.

If the reading is more than 3 volts less the battery voltage, the resistor is faulty.

If the voltage is the same as the battery voltage, replace the solenoid.

 



PDS TEST AT THE 10 PIN CONNECTOR OF THE CONTROLLER

Place the (+) probe on the red wire terminal of the connector.

If battery voltage is not present, the red wire between the Run-Tow/Maintenance Switch and the Ten Pin Connector is faulty.

Place the (+) probe on the black wire terminal of the connector. The reading should be slightly above 14 volts but LESS than 16 volts.

If the voltage is below 14 volts, the Throttle Sensor MAY be faulty. Above 16 volts, the controller MAY be faulty.

Separate the (6) six pin connector (only 4 are used) between the pedal box and the controller. If the voltage goes to 14-16 volts, the sensor is faulty.

If the voltage remains below 14 or above 16 volts, the controller is faulty.

RECONNECT the (6) six pin connector.

Place the (+) probe on the white wire terminal of the six pin connector. Depress the pedal slowly. The reading should be 0.45 - 0.53 volts just as the micro-switch is activated.

Depress the pedal slowly to full throttle. The reading should move smoothly to about 1.5 volts.

If the reading is incorrect, The Throttle Sensor is defective.



MOTOR UNWANTED CONTINUITY TEST

The following tests can assist in troubleshooting.

Disconnect all wires to the motor and label them

Make sure none of the terminals are grounded to the motor or cart (F1 terminal to motor frame) You should have continuity present between F1 and F2 and A1 and A2 but NOT BETWEEN ANY A and ANY F Terminal.

If any of these test fail, the motor will not operate correctly. 

I hope this information has helped.  

I regret there is not enough time in a day for me to personally walk everybody through their cart diagnostics.

If you need assistance please post on buggiesgonewild.com I will look for your posts there. 

Micro Switch Testing

The micro switches are simple 2 wire on/off switches. They open and close mechanically. 
You can test function with a voltmeter if you first verify 36v in on the supply side of the switch, then mechanically trigger the switch, and test for 36v on the output side. 
With the multi-meter set to continuity or ohms you can disconnect both sides of the switch and connect it to the meter. The meter will show the connection making and breaking. If not check meter settings and test a different switch. Once you are certain your test method is correct retest the switch in question.

Ezgo Series High Amperage Circuit Testing


​Put F/R lever in Forward and connect the Black test lead to the B- terminal on the controller and connect the red test lead to the M- terminal on the controller.

Press the pedal just far enough for the solenoid to click and you should read full battery pack voltage (38.2V if batteries are fully charged.)

The purpose of having the solenoid engaged is to send current through the solenoid mains from battery B+ to controller B+. 
The solenoid should be engaged anytime the pedal is depress, whether that is a small amount or pushed to the floor.
CAUTION. Anytime you are testing a no go cart it must be up off the floor in the rear because it may start unexpectedly while testing which may cause body and property damage.
SO when positioning the pedal for testing you have to ask yourself - If it does start unexpectedly do I want a slow start or a full speed start? 
If you are using a brick to hold the pedal down for testing put an appropriate amount of wood or ? under the pedal to avoid depressing the gas more than is needed to engage ( close) the solenoid 

If you don't get full battery pack voltage, move the red test lead to the A1 terminal on the motor, then to the A2 terminal, then to the C terminal on the F/R switch, then to the B terminal on the F/R switch, then to the S1 terminal on the motor, then to the S2 terminal on the motor, then to the D terminal on the F/R switch, then to the A terminal on the F/R switch, then to the B+ terminal on the controller, then to the Controller side large terminal on the solenoid, then to the battery side large terminal on the solenoid and finally to the main B+ terminal on the battery pack.

Stop at the point where you find the battery pack voltage and the problem will be between there and the last place checked that didn't have it.

Ezgo Troubleshooting

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