DCS solenoid no click hot resistor

[RCR808]

Troubleshooting an EZGO DCS cart that has fully charged batteries ~37.***V
Batt side of sol Vref, cont side of sol 35.5v, coil posts Vref. Pedal depressed no click. Checked ITS input 12v(<14-15v) output 0.5v(w/in 0.4-1.5v). So replaced Controller same problem, so I tried replacing the ITS same readings at input and output. Also realized that the solenoid resistor is extremely hot, with key off or FnR in neutral the resistor cools down but with key on and in fwd or rev resistor gets extremely hot w/o depressing pedal. Replaced solenoid still the same problem resistor heats up. I’m out of ideas and puzzled unless the new controller was bad to begin with?

[JohnnieB]

Fully charged batteries ought to be 38.2V or higher.

Solenoid not clicking is why the resistor is getting extremely hot. Contacts not closing, so the motor is trying to draw amps through the 250Ω resistor.

Apparently, B+ is getting to the solenoid coil since the controller is trying to pass amps and the solenoid's small terminal with red and yellow wires on it is in parallel with Pin-6 on the controller, which powers up the controller. Looks like the pedal switch is bad, if not the controller might be bad. (But that would make two controllers with same failure, so I suspect it is the pedal switch.)

BTW: Better take a closer look at the ITS voltages.
Pin-2 ought to be from 14V to 16V. You have 12V, so it is out of specs.
Pin-1 ought to be 0.45V to 0.53V when pedal is pushed just far enough to make solenoid click and from 1.50V to 1.75V with pedal on floor.

DCS ITS testing from service manual attached and a schematic.

[RCR808]

Yes I am aware of Pin 2 being out of spec, which I suspected the ITS being bad therefor I replaced ITS and no difference still reading 12volt. I will try a new pedal switch, thank you for the tip. By the way you’re 38.2v or higher on newer fully charged (well)maintained batteries!!

[RCR808]

...correct...

[JohnnieB]

Originally Posted by RCR808

1. Yes I am aware of Pin 2 being out of spec, which I suspected the ITS being bad therefor I replaced ITS and no difference still reading 12volt.

2. I will try a new pedal switch, thank you for the tip.

3. By the way you’re 38.2v or higher on newer fully charged (well)maintained batteries!!

1. There is an in-line connector it the end of the gray cable where it joins the cart's wiring harness. When the connections get corroded, the ITS voltages can get weird. Replacing that in-line connector with individual butt-splices or solder joints and sealing air tight with marine grade (adhesive filled) shrink tubing takes care of that issue.

2.

3. True, but an at-rest voltage of ~37.***V could mean a bad charger or other issue as well as old and poorly maintained batteries.

[RCR808]

So another day of troubleshooting before replacing the pedal micro switch I double checked the symptoms and I have discovered I may have MISTAKENLY gotten the Pins crossed. Pin 1 has the reading of 12v and Pin 2 was 0.5v. I was probably frustrated and crossed eyed, long day. So next I disconnected the 4wire 6pin plug between the main and grey harnesses. Probed Pin1 and still was reading 12v, I believe at this point Controller is Faulty?

[JohnnieB]

The DCS was EZGO's first attempt at a sepex drive system and the controller they used (Curtis 1206SX) had some design issues, so replace it with an Alltrax XCT48400-DCS (or larger), which is user programmable.

[RCR808]

Sounds like a good idea! Was thinking about going aftermarket. Thanks appreciate the help!