Please Help Me With 1992 EZGO Marathon Key Switch Wiring

Stuart

New Member
I just bought this 1992 EZGO Marathon golf cart that had the ignition key switch out and I can't follow any of the wiring diagrams to get it reconnected. One wire is easy it goes to the nearest battery terminal. It's the other one that I'm having trouble with, and of course, there are two or three wires that are not hooked up, so I need a little help with figuring out where they should be connected. I'm afraid I don't even know what certain components are called, but there is the forward and reverse switch which has a thin black wire coming out of it that is not hooked to anything, and there is a slightly larger gray wire coming out of it that is not hooked to anything. You'd think that by trial and error I could figure it out, but all I get is one click when I turn on the ignition and no movement. I'll post a picture of the wires I'm talking about. I don't want to cause any damage to it, so I'm trying to be careful about messing around with it too much. Thanks.
 

HotRodCarts

Cartaholic
There should be two wires going to the key switch. The red wire goes to the battery pack main positive post and the blue wire goes to micro switch two on the forward and reverse switch. Here's a link to a pretty good wiring diagram for a EZGO Marathon with controller. Welcome to the forum. :hattip:
EZGO Marathon Wiring Diagram - Controller
 

Stuart

New Member
AAC5A64E-0EE2-4206-9C87-82B2635A4047.jpeg

Thank you for the diagram. It is better than the one I had. There is a thin black wire coming from the controller that I can’t figure out. On the diagram I saw a back up warning device. Would that have been on my 1992 model?
Also, how can I test the solenoid to see if it is working?
Many thanks,
Stuart
 

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HotRodCarts

Cartaholic
The thin black white on the controller should be connected to the other micro switch on the forward and reverse switch. You'll need to get the golf cart wired correctly before testing the solenoid. Yes a 1992 EZGO Marathon would have a back up alarm. The golf cart will run without it if yours doesn't have one.
 

Stuart

New Member
Hi Cartaholic,

I wanted to let you know where I'm at with this thing. I've figured out what all the components are now, and have tested the solenoid and motor. Both appear to be working fine. I get continuity on the high voltage terminals when I energize the low voltage terminals, and it's clicking. So I am assuming it is OK. And I got the motor to turn when 12 volts was applied to it directly
. I also took a closer look at the thin black wire coming from the forward reverse switch, and realized it is hooked to the reverse signal. So that wouldn't prevent the cart from moving. I'm going to test the controller next, and then see if I can find instructions on how to test the forward reverse switch next. If those are both OK, I guess the only thing left is the potentiometer. Sound reasonable?

Thanks,
Stuart
 

HotRodCarts

Cartaholic
Does the solenoid click with the key on when you press the throttle or are you manually energizing it? If the solenoid isn't clicking with the key on when you press the throttle pedal test the micro switch on the throttle first.
 

Stuart

New Member
I tested both microswitches on the forward and reverse switch, and they both work fine. I cleaned up some terminals, put it all back together, tightened the battery connections, and voila, it moves! It only made it about 30 feet though and then it wouldn't come back up the driveway which is uphill. It has brand new batteries which I hadn't charged so I've got it on the charger now to see what happens next. If they charge fully and it's slow, what could that be? Thank you for all of your help.
Stuart
 

HotRodCarts

Cartaholic
Usually it would be from low voltage or bad batteries but seeing how your batteries are new I'd let them fully charge until the battery charger shuts off and see how it runs.
 

Stuart

New Member
Hi,

So now, I let it charge for a while and the battery indicator indicated they were charged. I jump on, and it moves forward and backward, but not at a normal speed. It's pretty slow. I moved it back and forth on level ground for a while, and decided to take it down hill to the street (like 30 feet). I get it on the street and it only goes a little and is pretty much dead again. I get off it, and let it sit for 20 minutes or so, test the batteries (still fully charged), jump on, put it in reverse, and it takes off like a rocket! I let it go for 20 feet or so, stop, put it in forward, and nothing. That's the latest. I think I'll give all the terminals a good cleaning and try again. It's got to be either corrosion on a terminal, the controller or the device that regulates the speed (connected to the gas pedal). Any advice you can give me would be appreciated. P.S. What does the controller do exactly? All I know is that if it is bad, it is very expensive to replace. I'm trying to fix this thing up to sell and make a profit on so I'm trying to do all this as economically as possible. Thanks again.
 

Nubs

Cartaholic - V.I.P.
I would check the pack voltage with digital volt meter and post number, the meter on the charger is not good enough to go off of:twocents:
 

Stuart

New Member
Thank you Nubs. I will check the voltage and post what it is.

And, am I correct that some '92 Marathons have a resistor coil that regulates voltage and speed, and some have a potentiometer that does the same thing? I don't see a coil on mine with 4 wires coming off of it. It looks like a potentiometer that I've seen somewhere while doing research.

I just went out to try and move it again, and it won't budge.
 

Nubs

Cartaholic - V.I.P.
Sounds like the problem is deeper than i can help, one of those smart fella's will be along soon

:hattip:
 

HotRodCarts

Cartaholic
Clean all of the battery cable connections and then let the batteries charge completely until the battery charger shuts off before doing any more testing. A 92 EZGO Marathon like you have doesn't have resistor coils it has a electronic controller and a potentiometer for throttle control. There's a post in the EZGO Resource section of the forum with details for testing the potentiometer. Here's a link.
EZGO Throttle Pot Box Potentiometer Testing Procedure
 

Stuart

New Member
I'm going to have to do it again to get you that information. I will test it again and determine the ohms at full throttle.

Meanwhile, I have replaced the solenoid with a brand new one, and it was not the problem. I have a question about it though. There is 36 volts when the key is on or off, across the large terminals. Zero volts across the small terminals. When the key is on, and I depress the pedal, there is 36 volts across the small terminals, and it goes to zero across the large terminals. That doesn't make sense to me, but would that be correct?
 

HotRodCarts

Cartaholic
No something isn't right. There should only be 36 volts on both large solenoid terminals when the key is on and the throttle is pressed to activate the micro switch on the throttle that activates the solenoid.
 
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