Ez-go pc955

[JDC]

Can someone tell me what year this cart is and what eletric system it has . It's a Ez-Go textron Model # PC955 UL23525 K3099 Controller model # 1205-122 This thing does nothing.

[JohnnieB]

Your cart is: Model Year: 1999 Make/Model: Electric 955 Shuttle

The controller is: 24-36 volt, 400 Amp for a Series wound motor.

The electrical system is most likely, six 6V batteries connected in series for 36V.

It does nothing, so the first question is: What is the battery pack voltage?

[JDC]

Thanks JohnnieB I thought it was a 99. This is what Ive checked so far. Batteries are at 36.7, took the F/R switch apart and it was clean, did the motor test and it work, replaced the seliniod because it wasnt working but still nothing.checked all the micro switches with DMM they all have continuity one way or the other, the switch on the throttle lever under the seat has three wires one orange to to seliniod one orange to the F/R swicth and the centre yellow one to the dash panel but not hooked to anything. the wire to the seliniod has continuity and the small grd at the seliniod is good the + side of the seliniod has 36.7 volts and the other side has 28.8. Is there a wiring dia. on here somewhere because I couldnt find one that looked the same.

[JohnnieB]

First, get those batteries charged. 36.7V is only 60% State of Charge, so the plates are sulfating as we speak.

Also, put on jackstands with rear wheels off ground, so it doesn't take off unexpectedly and run over someone or something.

However, 36.7V ought to have been enough to get the solenoid to click, so I'm pretty sure there is a problem in the solenoid activation circuit and we need to get it sorted out before moving on to the high current (motor drive) circuit.

I'm not sure if the '99 PC955 had a Pot box throttle or a ITS, but you mentioned a throttle lever under the seat so, I'm leaning towards a potentiometer type throttle.

Does this schematic match? (MS-3 would be the microswitch on the throttle lever arm.)

If so, we'll have it going, or at least know what is wrong, fairly soon.

[JDC]

Ok I'm charging the batteries now and I noticed the speed control varistor is broken off one of the studs at the controler would that be causing the problem or is that another one when I do get it going. It has a PB-16 box that the throttle linkage hooks to. I also removed the orange wire off the seliniod and tried jumping 12v to it and had a large spark even tried 6volts still large spark like something is shorted out. And I did the motor test again and it works.

[JohnnieB]

While charging, wet cell Lead-Acid batteries out-gas Hydrogen and Oxygen, so causing sparks in a potentially explosive atmosphere might not be a good idea. Also wear eye and skin protection when working near the batteries, sulfuric acid gets on everything when they explode.

The varistor isn't needed to run. Same with the 250 Ohm resistor across the solenoid's main contacts and the diode across the solenoid coil.
Of the three, only the diode being shorted or installed backwards would keep the solenoid from activating.

Here is a simplified drawing of what we are troubleshooting at the moment.
Three switches, a coil, a few lengths of wire and some connectors.
Red is B+ to solenoid coil, Blue is B- to other side of coil.

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It is a 36V solenoid, so 12V probably won't activate it.
The fact you got a spark, says the coil is good, or the diode is shorted, or the diode is installed backwards.
Remove the diode, to eliminate it from the equation.
(Its purpose is to protect the microswitch contacts and isn't needed for troubleshooting)

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I'm not sure what a PB-16 box is. Can you post a picture of what the throttle box looks like.

[JDC]

Here's the throttle box pics . I'll remove the resister and diode and try it now.

[JohnnieB]

OK, it is a potentiometer type throttle instead of ITS, so the schematic is the correct one.

[JDC]

I removed the diode not the resister and the seliniod will work when I jump power to it but not from the throttle pedal is the orange wire on the seliniod to have battery pack voltage when the pedal is pushed it has nothing I have 30 volts at the key switch in and out is that enough. Is the switch on the pot box bad ? The diode is the small one right between the small terminals.

[JohnnieB]

Solenoid clicks when 36V is applied, Good news!

You should have full battery pack voltage to/from key-switch.
Anything less means bad switch contacts, connecting wires or in line connectors.
(I'm not sure if any in-line connectors exist in your cart, but if they do, unplugging and reconnecting will usually clean the connection.)

The diode is the small thingy between the small terminals.
As for the switches being good/bad. I'm not ruling any of the out yet.

With Key-switch "ON", F/R in "F" or "R", pedal pressed, and your DVM's Negative test lead attached to B- (either at battery pack or controller).
Start measuring voltage at B+ on battery pack and work towards Solenoid coil.
If you don't measure full pack voltage, fix whatever is between where your Positive test lead is and B+ on battery Pack.
(The mechanical connection isn't show on the drawing, but MS-3 is the microswitch on the pot box.)

Be sure to jack rear wheels of ground so cart doesn't run over somebody or something just in case it decides to take off unexpectedly.