Bad controller?

[Ezgo0602]

What’s up guys, this forum is a huge help to be able to pick you guys’ brain. I’m in the process of restoring a 2004 EZGO TXT 36V Series Cart. Put new batteries, all new 4 gauge cables (motor cables also), new solenoid, new ITS under floor mat. Cart ran when it wanted to when I first put the batteries in it. Would run, then slow down to a crawl. Let it sit overnight, would run again the next day for a few minutes, then down to a crawl again. The last time it ran it made a jerking motion and died; hasn’t ran since.

Spent last night putting the meter to everything again. 38v going into controller, only 15-20v coming out going to motor. Pretty sure my controller is bad. As I left the key on and in forward gear while troubleshooting, the solenoid got extremely hot; so hot I can feel the heat coming off of it, couldn’t even touch it. Turned everything off and called it a night.

Woke up this morning, turned key and pressed the pedal and the cart took off. It’s done this before, it will likely only run until something gets hot again and shuts off. Note: solenoid is new. Can it be a “bad” new solenoid? Or bad controller causing things to overheat? Or both?

Thanks in advance!

i would redo the micro switch in the ITS area

[Ezgo0602]

Originally Posted by crash test dummy

i would redo the micro switch in the ITS area

I have a New microswitch but haven’t installed it. When I tried to install, the little rocker arm on it sticks out too far and won’t allow the pedal to press. Would a microswitch cause a controller to overheat and not send proper voltage to motor?

yes it would keep you from going .... the jerking was my frist clue ... you need the proper micro switch

[cgtech]

I'm not sure you are measuring things correctly here.... If the motor had 18v B+, and the B- to "back it up" it would be doing at least 7 mph while you were doing the readings (assuming motor is good, and I am not saying motor is bad, just measurements bad, it's all about reference). The motor is normally supplied "all the voltage" as far as B+ goes. It is regulated by it's access to B- (commonly referred to as "ground", which isn't a thing in modern electric golf cart world). Your circuit reading as low as it does, not full voltage, means the controer might be bad, the power source might be bad, the solenoid might be bad, the motor might be bad. You need to think about this the opposite way you might think of a car. The "ground" is what is "turned up, or down" to control the motor speed. And having a lower than "full pack voltage" reading is the thing is suspect here.

[radioman]

Originally Posted by Ezgo0602

I have a New microswitch but haven’t installed it. When I tried to install, the little rocker arm on it sticks out too far and won’t allow the pedal to press. Would a microswitch cause a controller to overheat and not send proper voltage to motor?

I don't think a pedal microswitch would cause the problems you describe. The microswitch causes the solenoid to energize when the pedal is slightly pressed and you should hear the solenoid click. One other suggestion is to protect against sudden unexpected movement working on this cart. Best to put rear on jack stands.

[nickdalzell1]

It sounds more like a speed sensor fault to me, if it is slowing down it's going into limp mode. Or low voltage could cause it. jerking sounds like one or more bad batteries.

[biphase]

A series cart will not have a speed sensor.

[radioman]

Here we go again. Guessing without doing some troubleshooting. Might as well check the air pressure in tires. My guess is you should check the small molex plug between the pedal box and the controller for corrosion while you are looking around. However it is not likely causing solenoid to get hot. A solenoid gets hot because of, but not limited to, high current passing through it, wrong coil voltage, faulty contacts. Voltage measurements on the big terminals when it is getting hot.would help diagnose where the trouble(s) might be.

Originally Posted by radioman

Here we go again. ~oltage measurements on the big terminals when it is getting hot.help diagnose where the trouble(s) might be.