EZGO TXT suddently stopped working

[RickiHN]

Hi
We own a 2002 EZGO TXT that we have had for a couple years now. We put brand new batteries in it and it has be working perfectly until recently. One day when out driving I removed my foot from the speeder and came to a halt. Then when I pressed the speeder again nothing happened. No click from the solenoid, nothing. The batteries were fully charged and there had been no signs of trouble before this.

I had it towed it home(turning everything off and setting it in tow mode) and noticed that it had a diagnostic mode, and thought I would give it a try. I had previously disabled the acoustic alarm due to it scaring off wildlife etc. but I quickly hooked it back up. But following the instructions yielded not even the smallest sound. So I tried turning the cart on and choosing reverse and still no sound from the acoustic alarm.

Next I checked the batteries which were fine, bit over 38V. Measured the voltage on the terminals on the solenoid, 38V on one side, 36.6V on the other side just like I read somewhere that there should be. So there is power to the solenoid and the control unit all right.

I disconnected the different switches and ran a continuity scan on them, seems to be in order as well. Only thing left I could think of was a fault in the control unit itself, so dismantled all the cables(removed leads from the batteries as the first thing of course) and ended up sitting there with a black box that I saw no way of opening without potentially causing more trouble than solving.

So my big question: Have I missed something? Is there something other than the control unit that could be faulty? Does the control unit contain fuses that could have shorted or relays that could be faulty? Would it be worth it for a somewhat novice like me to attempt to open it to look for faults?

[scottyb]

Put everything back together and tell us if the solenoid clicks when you try to go or not?

[RickiHN]

Originally Posted by scottyb

Put everything back together and tell us if the solenoid clicks when you try to go or not?

As mentioned it the first paragraph, it does not. There is the little click from the speeder pedal switch, but that's it.
But a faulty solenoid wouldn't explain that nothing else works, would it? Isn't the acoustic alarm supplied from the control unit? After all it is supposed to work even when "ignition key" etc is turned off for the diagnostic mode.

If it was a matter of everything else working just fine but the solenoid not triggering, then certainly it would be the solenoid. But it seems more like the solenoid(and everything else) is not receiving pilot power. And I am not great at reading diagrams etc, but isn't everything low amp supplied/controlled from the control unit?

[rib33024]

Welcome to BGW

sounds like the reed switch could of went bad, could be the controller, could be a few things, but you can't test the carts electric parts with it all apart, i'm guessing this is a PDS cart, is the cart lifted with big tires or stock cart? is the F/R switch on the dash?

[RickiHN]

Originally Posted by rib33024

Welcome to BGW

sounds like the reed switch could of went bad, could be the controller, could be a few things, but you can't test the carts electric parts with it all apart, i'm guessing this is a PDS cart, is the cart lifted with big tires or stock cart? is the F/R switch on the dash?

Yes from what I can understand its a PDS(not sure what that means though :P). The direction control is on the dash next to the key, and its a 2002 model. Its the regular golf cart model with normal grass tires.

I will connect the controller back up again. Easily done with all the modular connectors.

[scottyb]

There are half a dozen switches which much must be activated for the solenoid to click ( engage). The controller supplies only one side of the solenoid activation circuit. With the wheels off the ground…
Test the solenoid operation by checking for both positive and negative at the small terminals when the key is on and the throttle pedal is pressed. If needed, manually supplying the missing positive or negative activation voltage with jumper wires from the main pack to test operation.

Use the diagram supplied below to troubleshoot the solenoid activation circuit.

[RickiHN]

Originally Posted by scottyb

There are half a dozen switches which much must be activated for the solenoid to click ( engage). The controller supplies only one side of the solenoid activation circuit. With the wheels off the ground…
Test the solenoid operation by checking for both positive and negative at the small terminals when the key is on and the throttle pedal is pressed. If needed, manually supplying the missing positive or negative activation voltage with jumper wires from the main pack to test operation.

Use the diagram supplied below to troubleshoot the solenoid activation circuit.

Assembled it all again and checked the reed switch in the charge socket(didnt actually know it was there) and it works fine. It outputs the 38V by default to the control unit.

Measuring the voltage on both of the 2 smaller terminals(relative to the negative battery pole) on the solenoid yields 3.5V on both if forward is selected and 2.5V if backwards is selected. They both drop to respectively 3V and 2V if the speeder pedal is pressed. Where on earth do these voltages come from? Some residual left over from the voltage drop over the diode/resister/whatever?

Since it reads the same voltage on both terminals of the solenoid, I guess the coil is intact and the problem does indeed lie in the supply of the pilot power?

[kgsc]

Go look at the pic Scottyb attached, put the neg lead of your VOM on the main neg battery pack post and start tracing

[RickiHN]

Originally Posted by kgsc

Go look at the pic Scottyb attached, put the neg lead of your VOM on the main neg battery pack post and start tracing

Ahh right, I assumed some of those circuits triggered on negative, but all the red underlined are supposed to trigger on positive?

[RickiHN]

Measured relative to the negative battery pole:
Reed Switch(RED/WHT): 38V
Key switch(WHT/YEL & YEL/WHT):3V
Pedal switch(RED):3V (GRN pedal pressed):3V

Switches etc are working fine in the sense that they do cut/pass the 3V when triggered. But why is the control unit only outputting 3V?