Resistor/Diode on solenoid overheating

[mkwill]

My 2003 ez-go just stopped dead one day. It was like someone pulled a battery cable. I knew the issue was something besides the batteries but since they were pretty old I changed them and all the connectors out anyway. (36 v) When I started troubleshooting I found two burnt wires on the solenoid, burned in the middle not on the connection ends. I changed them out but that didn't solve the problem. Upon further inspection I found that the diode/resistor (?) that connects the two larger posts on the solenoid was too hot to touch. I assume this is what burned my other wiring. I don't know much about the cart but using techniques learned from this forum all my voltages seem to check out. Any ideas why this wiring would be getting so hot? It reads 38 volts when I attach my meter to the wires shown in the attached photo, is that normal?

[Restoredude]

so the cart still does not run but the resistor gets hot? does the solenoid click when you press down on the pedal?

[mkwill]

No, the cart wont do anything and the solenoid does not click.

[JohnnieB]

The black thingy connected between to two larger terminals on the solenoid is a resistor.
The black thingy connected between to two smaller terminals on the solenoid is a diode.

The resistor is getting hot because the solenoid contacts are not closing and the controller is trying to pass amps to the motor.

The first thing to do is get the solenoid to click when pedal is pushed, then go from there if needed.

I'm not sure if you have a PDS or a series cart, but there is a diode across the solenoid coil (small terminals) so I'll guess it is a series.

Here is a schematic with the solenoid activation circuited highlighted.

A shorted diode could have caused the wires to burn, so remove it for the time being. (It is a protection device and cart will run without it, but needs to be reinstalled after troubleshooting)

[mkwill]

Much appreciated. Let me throw a new wrinkle into this issue. I removed the old batteries myself and took pictures to make sure I hooked the new batteries up right. The battery shop talked me in to bringing the cart in and letting them install the new ones. I was happy to do this, so I took the cart and the photos to the shop and left the cart. They hooked it up like the photos all right but they turned all of the batteries 180 degrees, exactly backwards. It's my fault that I trusted them and didn't notice what they had done until this morning when I was trying to troubleshoot the solenoid. I turned the batteries back to their original state but I have no idea what damage has been done. The cart acts exactly the same: doesn't run, solenoid won't click, etc. How would you proceed from here?

[JohnnieB]

Attached is the standard battery layout for a TXT cart.

If the main positive cable and main negative cables were connect to the solenoid/controller/motor backwards, it could have done some damage to the controller as well as burning up some wires.

Orient and connect batteries as shown in the diagram. (They don't have to be, but it makes troubleshooting from easier)

Next, what type drive system do you have? Series or PDS?
The F/R control on a series cart is a lever by your right knee and a PDS has a rocker switch on the dash as well as a Run/Tow switch on the controller cover.

In either case, remove the resistor and diode from the solenoid for the time being.
(They should be installed for operation, but not needed while troubleshooting.)

Getting the solenoid to click is the first step, but have to know which drive system to troubleshoot.

[mkwill]

It's a Series, meant to include that in the last post. I sincerely appreciate the help. My batteries are now hooked up exactly like your digram, but the positive and negative were definitely reversed at the battery shop.

[JohnnieB]

Okay, the schematic I posted earlier was the right one.

Start at the reed switch. Check for B+ on the small white wire coming out of the cart's charge receptacle.
That is were the voltage that energizes the solenoid originates.

From there it goes to MS-2 on the F/R assembly, then to the keyswitch, then to MS-4 in the pedal box and finally to one of the small terminals on the solenoid.

Any or all of those switches might be blown.

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In a series cart, the solenoid activation circuit is entirely external to the controller, so it should click whether controller is good or bad.

[mkwill]

Johnnieb,
Thanks so much for all your help. I have been out of town and just got an opportunity to look at my cart again today. The reed switch was blown. I by-passed it for the time being, put everything else back and the cart runs great. This forum is a great resource. Thanks again.

[susie542001]

My resistor/diode on a 2014 txt keeps blowing.....bought a new one and it burned up right away. I recently replaced my batteries, and the cart was running fine, although my lights do not work, and then after going on a ride with no problems, got back on to go again, and the cart would not move. That is when I discovered the resistor/diode wire was blown and replaced it, only to have it blow again immediately. Any idea's what will cause that so I don't keep blowing them?