EZGO TXT 2002 is my new controller bad?

[cburgess129]

I think the new (remanufactured) speed controller in my cart does not work.

History:
My old (stock) controller on my 2002 TXT EZGO blew a few weeks ago. It had been going bad for a while and when it went it took out the solenoid (fused), melted a battery lug (required new battery), fused a connection on the FR mechanism and took out the key switch.

I have replaced all of the bad parts with new ones and a remanufactured controller with 6 control and B+, B-, and M- connectors. I verified the inductive throttle is good and verified the reed switch in the power plug port is good.

I pulled the wires off the motor, cross-connected it as described in the testing guide, connected it to 2 batteries (12V) and it ran fine, so I assume it is good.

When powering up the cart now I get a click from the solenoid but no drive.

Here are the measurements I have made:

Pack voltage 37.6

Controller Pin 4 With FR Switch in Forward, Key Switch On, and Pedal down: 34.8V

Controller Pin 3 With Direction Selector Switch in Forward, Key Switch On, and Pedal down: 0V

Controller Pin 3 With Direction Selector Switch in Reverse, Key Switch On, and Pedal down: 37.4V and buzzer sounds

Controller Pin 2 With Direction Selector Switch in Forward, Key Switch On, and Pedal pressed enough to make solenoid click: 14.6V

Controller Pin 1 With Direction Selector Switch in Forward, Key Switch On, and Pedal pressed enough to make solenoid click: .507V (half a volt)

Controller Pin 1 With Direction Selector Switch in Forward, Key Switch On, and Pedal fully depressed: 1.52V

Controller readings with FR switch in forward, battery on, pedal full down

B+ to B- 37.6 steady (does not drop)

B+ to M- 37.6 steady (does not drop)

B- to M- starts at .2v with pedal up and goes to 0v with pedal full down

Solenoid reading after sitting for 30 minutes with key off, resistor removed

battery side: 37.6V

controller-side .9V

Solenoid reading with key on, FR switch in forward:

push pedal - solenoid clicks voltage at controller side goes to pack voltage 37.6V


Please advise further testing.

[JohnnieB]

Originally Posted by cburgess129

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B- to M- starts at .2v with pedal up and goes to 0v with pedal full down
......................

The correct B- to M- testing is:
1. Press pedal just far enough to make solenoid click and you should read full battery pack voltage. (38.2V when fully charged)
2. Voltage ought to decrease to 0V as pedal is pushed to floor.

Looks like B+ is not getting back to the M- terminal, so the is an open or high impedance connection in the high amps cables, connections or contacts. F/R switch is most likely suspect.

Attached is a series drive schematic with high amp circuit highlighted.

[cburgess129]

Turns out it was the forward/reverse switch. The current was not making it through the lugs to the motor and back to the M- connection. It had to be very tight to make a good connection between the lugs - so tight it was hard to move the lever.

I took it apart, scuffed the pads on the rotating assembly and lubricated the shaft and back washer and now it shifts smoothly and makes a good connection and the cart runs great.

[cbdeese61]

You should seriously look into changing over to a reversing contactor. I did and have not regretted that decision. It has been great.