EzGo 2005 Clays Car does not operate

[Carts4you]

Hi. I have been working on a Clays Car which was operating and all of a sudden stopped working. A new F/R switch was installed and then it operated for a few days. Then again it stopped working. We have run through the troubleshooting for the Electric Control System and found that the solenoid had been replaced but the diode nor the resistor had been installed. We installed them and ran testing again, which gave good voltage readings but no operation from the motor. According to manual, this would mean a short, mechanical obstruction or bad motor. We do not see any short or mechanical obstruction. We tested a new 36 v motor but we did not get any response. Any idea on what it could potentially be?

Thanks any info you can provide.

[islandcartsmacpro]

Originally Posted by Carts4you

Hi. I have been working on a Clays Car which was operating and all of a sudden stopped working. A new F/R switch was installed and then it operated for a few days. Then again it stopped working. We have run through the troubleshooting for the Electric Control System and found that the solenoid had been replaced but the diode nor the resistor had been installed. We installed them and ran testing again, which gave good voltage readings but no operation from the motor. According to manual, this would mean a short, mechanical obstruction or bad motor. We do not see any short or mechanical obstruction. We tested a new 36 v motor but we did not get any response. Any idea on what it could potentially be?

Thanks any info you can provide.

Okay so test the s1 and s2 or f1 and f2 ( which ever you have ) across from your a1 post. Push gas peddle with wheels off ground and see if voltage goes to 0 from 36 as you increase throttle. If not then the controller isn't sending power to the s1-s2 which could be from the resister not being on... Its job is to let small voltage pass to keep controller alive so when you turn the key it has power and doesn't get hit with a surge of power waking it back up... That can damage a controller..

Sent from my SM-N900V using Tapatalk

[JohnnieB]

Originally Posted by Carts4you

Hi. I have been working on a Clays Car which was operating and all of a sudden stopped working. A new F/R switch was installed and then it operated for a few days. Then again it stopped working. We have run through the troubleshooting for the Electric Control System and found that the solenoid had been replaced but the diode nor the resistor had been installed. We installed them and ran testing again, which gave good voltage readings but no operation from the motor. According to manual, this would mean a short, mechanical obstruction or bad motor. We do not see any short or mechanical obstruction. We tested a new 36 v motor but we did not get any response. Any idea on what it could potentially be?

Thanks any info you can provide.

Neither the pre-charge resistor nor the diode is necessary for the cart to run. They are protective devices for the solenoid contacts and various switch contacts, so they last longer.

The first step is to determine what type drive system the cart has, series or PDS, but I suspect it is a series drive.

Next is determining if problem is in the solenoid activation or in the high current circuit.

Does the solenoid click when pedal is pushed?
If it does the problem is in the high current circuit.

[Carts4you]

Thank you JohnnieB and Islandcartmacpro. The cart worked without the resistor or diode. We installed them after it stopped working to get proper readings during our troubleshooting. I will need to see the S1/S2 voltages and get back to you.

The solenoid does click. What are the high current circuit parts or connections? Controller, batteries, motor, solenoid? The solenoid installed used to work with the car and it ran. Could it be that the solenoid cannot manage the voltage/amps? I know it has been changed to a different one from original one. Much smaller but still 36 volt

Thank you both!

[Carts4you]

Well I verified the s1/s2 and we are getting reference voltage on both posts at motor. I did notice that all posts receive the reference voltage when depressing the pedal all the way.

[JohnnieB]

The high current circuit consists of the battery pack, all 13 heavy gauge cables, the F/R switch's high current contacts, the solenoid contacts, the MOSFETs in the controller and the motor. The ITS throttle system governs the duty cycle of the MOSFETs, so it is indirectly part of the high current circuit, rather than a direct part.

Attached is a schematic of a series drive with the high current circuit highlighted.

With rear wheels off ground and cart on jackstands, so it doesn't take off unexpectedly and run over someone or something:
Measure and note the battery pack voltage, then connect your DVM's black test lead (negative) to the controller's B- terminal and the Red test lead (positive) to the M- terminal.

Press pedal just far enough to make solenoid click. You should read the battery pack voltage. (38.2V if fully charged)

FWIW: The MOSFETs are located between the B- and M- terminals and should have 0% duty cycle when the pedal is only pushed far enough to make solenoid click, so you are measure across the only open that should exist in the series circuit and should read the entire applied voltage.

If you dodn't, there is an open somewhere in the high current cables, connections or contacts. The F/R switch is the most likely suspect. You ought to have 38.2V on all 4 studs with heavy cables attached to them.

Basically, when you find the missing voltage, you have found the problem.

[Carts4you]

JohnnieB I tested the system. We have a 1205 controller but it does not have a scanner port like some I have seen online. The reading between controller b- and m- is -.360 when solenoid activates and at full throttle drops to 0 volts. When letting go of pedal it goes up to reference voltage for a few seconds and then drops to roughly 17volts. Controller m- is connected to “A” stud on F/R switch. This cable looks good. I am thinking the problem may lay in the controller? I get reference voltage in all studs at motor when pressing pedal. The throttle readings are 1.6 at solenoid click and 2.6 at full throttle which is correct.

[JohnnieB]

Originally Posted by Carts4you

JohnnieB I tested the system. We have a 1205 controller but it does not have a scanner port like some I have seen online. The reading between controller b- and m- is -.360 when solenoid activates and at full throttle drops to 0 volts. When letting go of pedal it goes up to reference voltage for a few seconds and then drops to roughly 17volts. Controller m- is connected to “A” stud on F/R switch. This cable looks good. I am thinking the problem may lay in the controller? I get reference voltage in all studs at motor when pressing pedal. The throttle readings are 1.6 at solenoid click and 2.6 at full throttle which is correct.

If the voltage between B- and M- is only 0.360V when solenoid clicks, there is an open or very high resistance connection somewhere in the highlighted cables on the schematic I posted above.

You have a 1205 controller, so it control wiring has individual push-on type connectors instead of a single multi-pin connector like the 1206, but the high current connections are the same.

Although the ITS voltages are way down the list of troubleshooting steps, and we are on about step-3, are you sure of those voltages? I don't have a service manual for a Clays cart with HD controller, but in other carts with 1204/1205 controllers and ITS type throttle, the voltages are 0.4V to 0.6V when the solenoid clicks and 1.5V to 1.7V when pedal is on floor. As mentioned, checking the throttle, is way down the list, we are presently trying to get pack voltage between b- and M- when solenoid clicks.

[Carts4you]

Hi JohnnieB. Please see the attached reading specs from manual for a Clays Car with 1205 controller. Reading are according to these specs. Could it be the controller failing?

[JohnnieB]

Looks like the throttle voltages are correct.

Since you are not getting battery pack voltage (38.xV) between the B- and M- terminals on the controller when the solenoid first clicks, the motor won't run whether the controller is good or bad.

Connect your DVM's black test lead to the controller's B- terminal and then measure the voltage on the four studs on the F/R switch with the red test lead. All four ought to have battery pack voltage.