1991 EZGo Marathon Electric Just Quit

[Danali]

***I put this originally under the wrong section. So sorry. I moved it to here after realizing the mistake****

I am a newbie, which by definition means I have a problem. I have a 1991 E-Z Go Marathon electric cart. We use it to run over our property servicing our rental houses. It is an essential piece of equipment, and I really need to get this baby running again.

Here is what happened. On an intermittent basis, just very recently, the cart simply stopped running in forward. Each time, I would put the cart in reverse, it responded immediately, I then put it back in forward and it would take off right away and run for quite some time. This cycle was repeated successfully and continued for a few days, then finally reverse refused to work also and cylcing from F to R did nothing anymore. One other key sympton is that the solenoid quit clicking when the accelerator was pressed. Batteries were fairly new and tested a strong (total) of 36 volts.

Here is what I have done (in each test of ohms I isolated the device):

1. I isolated the solenoid and checked for both performance and continuity. I applied 36 volts to the small terminals and then read ohms across the large posts. Each time I applied the 36 volts, it clicked and the solenoid closed showing 0 ohms and then showed open when the 36 volts was removed. So the solenoid seems fine.

2. I put the ohm meter on the Pot Box and the ohm meter moves like it should while moving the gas pedal, so it seems fine.

3. I tested the micro switch on top of the pot box and it closes and opens or makes and breaks like it should going from 0 ohms to open.

4. I was told by the local dealer that if I shorted M- and B- on the control box, that I would essentially take the control box out of the problem. I did so with no effect.

5. I accidentally shorted the main posts on the solenoid and the motor fired off. I took the precaution of having everything up on floor jacks so no problem. Anyway, the motor and wheels fired off to full speed, so I know the motor works.

6. I pulled the F/R micro switch that operates off the rotor of the manual F/R switch inside the cart. Although it is a double switch there is only terminals on one side only. The switch showed with the ohm meter that it operated correctly, making and breaking.

7. I am getting a good 36 volts from the batteries, and they are less than a year old. I am getting a strong 36 volts on the "left" side of the solenoid, but nothing on the side of the solenoid that then would send that 36 volts to the control box, which again just confirms that the solenoid is not making for whatever reason. If the blue wire is the problem then I have a control box problem. Ouch.

Bottom line, at least at this point. I can't figure why the solenoid isn't making. Should there be voltage between the small posts on the solenoid? The only mystery that I have been not been able to figure out is this: there is a blue wire that runs from the control box to the one side of the microswitch that sits on top of the pot box. It looks like that microswitch on top of the pot box must get something from that blue wire before it can make and affect the solenoid. If the blue wire is critical then the control box is definitely suspect.

I have researched this forum pretty thoroughly and found nothing to indicate if the blue wire is necessary for the microswitch and therefore necessary for the solenoid.

One other point, we were slammed by Fay and we have lost a lot of items such as carpet some furniture etc. The water line, however, is very clear on the golf cart and none of the electrical was under water. In fact I ran the golf cart for days after the flooding with no problem.

I am sure I have left something out, but have tried to include everything I can at this point. Any direction would be appreciated very much.

[Paxdad]

You may want to check the key switch and wire from switch to pot box micro.

[scottyb]

That micro on the pot box should have power in when the key is on. when the pot is first activated the micro should close sending power to the solenoid. Yes, the solenoid should have 36v across the two terminals when activated. One test for a bad solenoid is to jumper them (as you did when you shorted across the large terminals). So it appears you have a bad solenoid.

[Danali]

Originally Posted by Paxdad

You may want to check the key switch and wire from switch to pot box micro.

Thanks, I did check the key switch and wires. The ohm meter shows the switch operates properly.

[Danali]

Originally Posted by scottyb

That micro on the pot box should have power in when the key is on. when the pot is first activated the micro should close sending power to the solenoid. Yes, the solenoid should have 36v across the two terminals when activated. One test for a bad solenoid is to jumper them (as you did when you shorted across the large terminals). So it appears you have a bad solenoid.

Thanks for the reply. Do you happen to know what voltage I should see on the micro above the pot box when the key is on (36 Volts are some other voltage) ?? I am getting no voltage at all. Is it supposed to get the voltage from the blue wire running from the control box? It seems I am missing voltage on the micro above the pot box and also am missing voltage on the small posts of the solenoid. I never get voltage in either place.....I have tried by depressing the accelerator etc and voltage simply doesn't show up in either place, so naturally the solenoid never has the voltage to close it.

I did pull the solenoid completely out and applied 36 volts to the small terminals. I read ohms across the large posts and it opened and closed like it should with voltage applied and removed to the small posts. It seemed to work fine.

[rusty]

Welcome to the forum Danali...............

[Paxdad]

Originally Posted by Danali

Thanks for the reply. Do you happen to know what voltage I should see on the micro above the pot box when the key is on (36 Volts are some other voltage) ?? I am getting no voltage at all. Is it supposed to get the voltage from the blue wire running from the control box? It seems I am missing voltage on the micro above the pot box and also am missing voltage on the small posts of the solenoid. I never get voltage in either place.....I have tried by depressing the accelerator etc and voltage simply doesn't show up in either place, so naturally the solenoid never has the voltage to close it.

I did pull the solenoid completely out and applied 36 volts to the small terminals. I read ohms across the large posts and it opened and closed like it should with voltage applied and removed to the small posts. It seemed to work fine.

I may be wrong but you should not see volts across the pot box micro. You should be able to see ohms by placing the positive probe on the common micro post and the negative probe on the the other micro post, turn the the key on and place in fwd or reverse then depress the accelerator (while cart is jacked up for safety) and should see a reading indicating the micro is good.

I would also check the wire from the F/R Micro to the pot micro for current flow. Simply remove the wire and hook it to a know DC power supply and measure accordingly. My cart went dead once and this wire was the cause due to a faulty crimp.

[scottyb]

Originally Posted by Danali

Thanks for the reply. Do you happen to know what voltage I should see on the micro above the pot box when the key is on (36 Volts are some other voltage) ?? I am getting no voltage at all. Is it supposed to get the voltage from the blue wire running from the control box? It seems I am missing voltage on the micro above the pot box and also am missing voltage on the small posts of the solenoid. I never get voltage in either place.....I have tried by depressing the accelerator etc and voltage simply doesn't show up in either place, so naturally the solenoid never has the voltage to close it.

I did pull the solenoid completely out and applied 36 volts to the small terminals. I read ohms across the large posts and it opened and closed like it should with voltage applied and removed to the small posts. It seemed to work fine.

I think your ignition is running the full 36 nominal voltage and this is what you will see at the micros and small solenoid terminals. Your problem is the lack of voltage to the micros. So use the diagram for your cart and check the ignition switch and it's source. Once you have power going into the micro test it like a switch. Remember a switch only interrupts 1/2 of the circuit. I think you are well on your way to solving this one!

[Danali]

Originally Posted by scottyb

Your problem is the lack of voltage to the micros. So use the diagram for your cart and check the ignition switch and it's source. Once you have power going into the micro test it like a switch. Remember a switch only interrupts 1/2 of the circuit. I think you are well on your way to solving this one!

I haven't found an exact elect diagram for mine. More specific to your point, I am sure that the lack of 36 volts esp at the micro above the pot box is probably the problem. I still can't determine where the 36 volts comes to the ignition. However, the blue wire (that is still a mystery) that comes out of the control box and goes to the same terminal the ignition wire is on, on the micro above the pot box could be the source of the 36 volts. I am jumping to the only conclusion I see right now......that is, the 36 volts must be coming from the blue wire out of the control box to the same terminal on the micro above the pot box that the red ignition wire is on as well. If that is true, then the control box is at fault. I hate to assume that though. All the elect diagrams I have found do not show this specific area and the respective voltages. If that blue wire is supposed to supply the 36 volts to the one side of the ignition that would begin the journey of 36 volts that would continue on to activate the small posts on the solenoid.

Sorry to be so wordy......but if I am right, the control box is the problem. No joy in mudville over that. I guess I am going to drive to a local EZ Go dealer and run this all past them. I MISS my golf cart. We have 4 acres with 12 rental houses, and the cart saves gobs of time in running to each one to do work etc, not to mention all the work it does as well moving things.

[Paxdad]

The flow should be as follows:
#1 battery positive to;
Key switch common to;
Key switch non common to;
F/R Micro common to;
F/R Micro non common to;
Pot box micro common; Note: the pot box micro common is shared with a blue wire to the #1 input on the controller
Pot box micro non common goes to the small post on the solenoid.

Again this is the flow not the actual wiring diagram however, if you can picture the above in your mind you have the diagram.