EZGO TXT Runs for 10 Seconds Then Nothing

Diode

Cartaholic - V.I.P. Sponsor
I yes correct the key switch could also be dropping out or the control power just for a second 10 seconds is not normal for a controller failure it could happen but generally we're looking at one second and then dropping out so your solenoid is dropping out and then you have the failure correct.
 

Diode

Cartaholic - V.I.P. Sponsor
Controller has anywhere from three to five inputs that it needs to see all working before it pulls the solenoid on then the cart can go any one of those inputs can cause the controller 2 release the solenoid causing the car to go into your failure mode
 

HotRodCarts

Cartaholic
Inside the throttle box I found what looks like a magnet passing through a coil, meant to vary output current which I should be able to measure. Right?
That would be the ITS (inductive throttle sensor) and there's a test procedure in the service manual that can be downloaded from the resource section of the forum.
 

DaveyGee

Member
I went through the ITS test and the values are correct. However, in the Troubleshooting Chart (page E-5), Step 3, voltage measures only 6 volts prior to controller fault and 0.6 volts after fault. I removed the 250 ohm resistor (photo below) and it measures 247 ohms, close enough I assume.
I'm curious, why don't those "nail heads" have diodes between? See that one of them is bent, touching the resistor. No problem?
( I never noted before removing which way it connects to the solenoid. Without diodes it does not matter. Correct?)

Happy New Year to all!
 

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HotRodCarts

Cartaholic
Someone has done some hacking on the resistor/diode board. The board should look like this.

5556.jpg
 

DaveyGee

Member
My cart is a '97, not 98-99.
It's been working without them for at least 8 years. What are the diodes for? Fail-safe?
Which terminal do they connect to?
Do you think my hacked board affected the controller or is causing my problem?
 

HotRodCarts

Cartaholic
The solenoid diode prevents reverse voltage spikes. The band on the diode(s) should aim at the positive side of the solenoid. I would think the diode lead touching the solenoid resistor in your picture would/could definitely cause problems. With no diode on the solenoid the risk of damaging the controller with a reverse voltage spike is much higher. On a EZGO DCS golf cart the controller is VERY easily damaged to begin with even with the diodes in place. The low voltage reading on the controller side of the solenoid is probably caused from the controller being bad.
 

DaveyGee

Member
It sounds like that hacked resistor/diode board is the culprit. I've been reading about "flyback" diodes (Flyback diode - Wikipedia) and their purpose on solenoids. Since the resistor and board are okay I'm looking at replacing the diodes only, but don't know what value they should be. Amazon has: 15SQ045 / Forward Current : 15 A / Maxixum Repetitive Peak Reverse Voltage : 45 V Not sure if they will do the job?

It also sounds like I need a new or repaired controller. Would it make sense to change to a less sensitive system at this time? 1
 

DaveyGee

Member
I also found this from ElectricMotorsport.com:
A coil spike suppression diode is a protection device across the contactor coil. Energizing the contactor coil creates a magnetic field that forces the solenoid arm to engage the contacts. When the contactor is turned off, the magnetic field collapses causing a back “voltage spike” that can damage the controller. The diode safely suppresses this energy.
Note: Pre-Charge Resisters and Coil Spike Suppression Diodes are required with all Alltrax controllers but are not used with Curtis AC controllers or Sevcon controllers

The note is interesting as it states my Curtis controller doesn't need the suppression diodes.
 

HotRodCarts

Cartaholic
Note: Pre-Charge Resisters and Coil Spike Suppression Diodes are required with all Alltrax controllers but are not used with Curtis AC controllers or Sevcon controllers
That's referring to Curtis AC controllers and you have a DC controller and it requires the diode.

If it was my golf cart I'd go with a Alltrax DCX300 or DCX400 and a new resistor/solenoid board. The Alltrax DCX controllers are MUCH better than the Curtis DCS controllers. :twocents:

Alltrax may even recommend a different resistor and diode setup for the DCX controller so I would ask them about that. @Diode may be able to set you up with something also.
 

Diode

Cartaholic - V.I.P. Sponsor
If your controller is truly bad which we don't know yet I can either get it rebuilt or I do sell alltrax controllers but you need to make sure it's bad before you replace it and have the same problem with a new controller
 

Diode

Cartaholic - V.I.P. Sponsor
Will it go forward and reverse 10 seconds is generally too long for a bad controller it's usually not at all or a few inches so is 10 seconds a guess could it be one second
 

DaveyGee

Member
Initially I was able to move it 10' on level ground before it quit. At this point, with the wheels off the ground, it immediately cuts out after the solenoid clicks. The wheels don't turn at all.
 
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