Trouble shooting 1995 36volt ez go

ncseadad

Hey Guys, Working on a friends 1995 36 volt series model ez go. The cart hasn't been used in about 6 months. The first thing I did was clean, check and charge the batteries...All are good and holding around 38 volts. All cables and connections are good.
The solenoid clicks but the cart want move...In check the obvious the key switch, both micro switches on the F/R are working proper. However the micro switch in the peddle box was broken.
I have several issues with this cart but address only one at a time so I want get confused. My first question will be can I bypass the micro switch in the peddle box by connecting the red and green wire together and continue my testing until I get another one.

I will mention one other issue I have that I don't think has to do with the peddle micro switch and that is with peddle micro switch jumped, key on and cart in forward I have 38 volts on both sides of the solenoid. Solenoid clicks but does not move. When I disconnect the peddle switch or turn the key off or put in neutral the voltage on the far side of the solenoid still has 38 volts and very slowly drops down eventually to nothing. It does this with the diode and resister on the solenoid connected or disconnected.

OK guys. let me know if the micro switch being bypassed has to do with the rest of the checks and any ideas on the solenoid.

Thanks
Bill

BGW

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ncseadad

PS This is a series model and does not have a tow/run switch or a reed switch...

Bill

gotmud10

First place Id check is continuity in the ITS while your pedal is depressed. Im assuming it has ITS throttle input due to the microswitch in the pedal box. In the series cart, Im pretty sure the solenoid is activated by the microswitch in the pedal box (which is why its 38v when you have the microswitch jumped). Sounds like its just a bad ITS to me.

scottyb

The resistor will give a 36v reading on both ends. It sends a precharge voltage to the controller. The controller holds this charge for awhile after the resistor is removed. This is probably what you are reading. Jumping and bypassing is not the best way to test this system, better if you can just get another peddle box micro switch.
Bypassing the peddle box micro would essentially turn the solenoid on and power up the control when the key was switched on.

ncseadad

OK Thanks Guys....I ordered micro switch and should be here in a couple days...I will replace the broken one before I run any test, just to make sure...

Question: If I need further help on this cart after the micro switch is installed, do I post another thread or just come back to this one...Not sure if an older thread will come back up top with a new posting to it...

Thanks and will get back to you in a few days.
Bill

simple man

Yeah, keep it on this thread! A new post will come up on top. This way we can follow what you have done!

ncseadad

OK Guys...Bill is back...I received the new micro switch for the peddle control and installed...It seems that person prior to me had adjusted the peddle throttle to far back and it would not roll across like it should and broke. Now that is all good...

Solenoid clicks but still no go. I printed the ITS check for ez go from here and tried to do the checks. The first thing is to put in forward, key switch on, press peddle until it clicks/activates the solenoid and place a jumper across BL+ and small solenoid terminal with red wires..(I will assume BL+ is the 36 volt positive post on battery pack)
Well, here lies my problem, I have 37.2 volts on the big positive sided of the solenoid and already have 36.9 volts on the small solenoid post where the red wires are and on the other large post. So, with or without the jumper I have or almost have pack voltage on the small post on solenoid with red wires attached.

Form this point I did some of the other test below, and it shows the same with or without the jumper wire on.

Next test was to place red probe on red wire terminal at the connector. I had pack voltage with/without jumper

Next test was placing the probe on the black wire terminal of the connector and I had 14 volts again with/without jumper

The next step you disconnect the 6 pin connecter and if you don't have 14 volts your sensor is faulty or voltage remains below 14 the controller is faulty. I was not sure how to do that test. Not sure where your probes go..

Next test was probe on white wire on 6 pin connector reading should be between .045-.053 Mine fell in that area. Next was pressing the peddle slow and should go to about 1.5 volts...Mine went to 1.6.

Next was to probe between (M-) and (B+) Test said it should be 00 volts and I have pack volts. Slowly pressing the peddle had nothing to do with the voltage seeing how I already had pack voltage at the beginning.

So, that's where Im at right now. Some of the test were ok and some were not and I am thinking its maybe the solenoid.

I still have or almost have pack voltage on both large post on the solenoid and this is WITHOUT the resisters and dioade connected.

OK my friends...I will be waiting....
PS. I don't think the ITS or the controller would have anything to do with having pack voltage on both sides of the solenoid....(Just a thought)

So, what test should I start with....
Thanks
Bill

JohnnieB

First of all, lift the rear wheels off the ground (jackstands) so the cart doesn't take off unexpectedly and run over someone or something.
This will also allow wheels to turn with a marginal battery pack that may not be up to moving cart when on ground.

Second, remove any jumper wires that may have been added.

From your last post, it appears that the solenoid clicks when the pedal is pushed like it is supposed to and that the ITS voltage to the controller is within specs.

Having Battery voltage between the controller's M- and B+ terminals is troubling.
If you do, the wheels should be spinning, or something should be smoking.
But, it could be a phantom voltage reading due to the high input impedance of your DVM, since all it takes is a little dust and/or dampness between the controller's terminals to get some strange voltage readings
So, let's go at it from a different angle.

Connect your DVM between the controller's M- an B- terminals.
Press pedal until solenoid first clicks. (If the pedal microswitch is adjusted properly, the solenoid clicks before the plunger enters the sensor coil)
At that point, you should read FULL battery pack voltage between M- and B-. (Note emphasis on the word "FULL". If the pack voltage is 37.2V the voltage between M- and B- should be 37.2V)

If not: There is a bad cable and/or connection and/or set of contacts in the high current loop highlighted on attached schematic.
(I know the cart you are troubleshooting on does not have a reed switch, but the high current loop is the same)

If so: Gradually press the pedal to floor.
The voltage between M- and B- should smoothly decrease to Zero.
(If the motor is spinning, it will only decrease to near Zero due to a 0.3V to 0.5V developed across the MOSFETs per 100A of current flow through them)

If the voltage doesn't drop to Zero (or near Zero) the controller is bad.
(The fact that the ITS is telling the controller to pass current to motor was already established, so the controller is not doing what it is being told to do.)

Attached Images

Wiring Diagram - Series- Hi-Current traced.JPG (59.3 KB, 0 views)

ncseadad

OK JohnnieB...Cart jacked up, key switch on, in forward, and press peddle until it clicks with probes on M- and B- I have 2.5 volts...(suppose to be pack volt)...nothing happens when I push the peddle.

So you are saying I have something wrong in high current line you highlighted in red...If so, when I go to test should I have pack voltage everywhere in the highlighted red, from one end to the other...ie.. in and out of motor or in and out of F/R switch....etc.....

Bill

ncseadad

OK guys....while waiting a reply I checked the high current loop you highlighted in red....

With the key switch on, in forward and pedel pushed for micro switch to click at which time the solenoid also clicks...

with black probe on (pack negative (BL) ) I have pack voltage (37.1) at the following: on both large post of solenoid, B+, A, D on F/R switch, S2, S1 on motor, B & C on F/R switch and back to A2 on motor.

All my high current on the wiring diagram seems to be correct...NOTE: this test was done with out the resister and diode connected on the solenoid.

JohnnieB.....since I don't have voltage on previous test BUT I have correct current on high current...What is the next step...Do we need to back up...

Thanks
Bill