'05 Precedent Run Away Motor Situation...

[ThaWrenchPuller]

Hi, First off, I'm sorry for the long paragraph, but I need a second opinion. I have a 2005 Precedent that was non-operational. It would intermittently make an attempt to move, as if the solenoid was dropping out. While on jack stands, and testing things with a multimeter set to DC, I connected the probes to the small input connectors on the solenoid. Batteries at 51volts, and with the tow/run switch in the run position, keyswitch on, and the FNR switch in forward, I pressed the accelerator pedal four times. The first press, nothing, which is normal for a club car, I know. Second press, nothing. Still kinda normal. Third press, clicks twice and tires rotate slightly. Fourth press, wheels start rolling like there's nothing wrong with the cart. So I hold it for a minute to see if it's gonna shut down on it's own, when all of a sudden, it starts to run away, like a diesel engine. So I let go of the pedal, still going full send. So I shift to neutral, still going. Next I try the keyswitch, still going. Then I flipped the tow/run switch to tow, and it is still going, to which I hear the windings in the motor seperate and making an awful noise. At this point, the wheels are going so fast, the cart is starting to vibrate so hard, it's about to jump off the jackstands, so I grab a wrench and disconnect the batteries and it finally, gradually slows down until it comes to a stop. What would you suspect that would cause this?

[Fairtax4me]

Sure it's an 05? There was a throttle system used in 09 that would cause this sort of problem, but was only used for part of the year and was recalled almost immediately.

More than likely a bad controller I would think, but it's hard to say without seeing the cart. The controller is between the batteries on that year isn't it? Look for any signs of damaged wiring. If there is/was excessive corrosion on the batteries it's possible for that to get into the controller or other wiring under the seat area and cause big problems.

The wiring to the MCOR should also be checked. The pedal compartment under the rubber floor makes a great home for a mouse. Check in there for any chewed wires.

While the access panel under the floor is removed, look back under the floor towards the rear of the cart and look for the serial number sticker on the frame cross member That is often the only ID tag left on the cart and will verify which year production the cart is. Post the serial number if you can so we know exactly which year cart you're dealing with.

[WalterM6]

Did you see a spark when you connected the probes to the small input connectors on the solenoid? It sounds like the solenoid/safety contactor shorted closed. This is why they say never run these motors wide open with the wheels off the ground. After awhile running them they will self destruct. Taking out everything in the line.

[NoleFan4Ever]

Lots of things here stick out.

1- Pressing the pedal and not hearing a click tells me the MS in the MCOR is bad.
2- The controller needs an output signal to run the motor up (and you were off throttle)
3- The speed sensor on an IQ cart would prevent you from running over the speed code setting while on the jack stands.
4- Power was coming from somewhere so as Walt mentioned, there could also an issue at the main contactor (solenoid) or a short somewhere.

Now time to start troubleshooting one part at a time. I would start at the MCOR (which is under the floor board) and then the solenoid next. You could also have a damaged harness causing a short. The first thing that stood out at me was your post states when depressing the pedal nothing happened, which is NOT correct, as you should have heard the MS (micro-switch) click.

[NoleFan4Ever]

Unplug the two pin connector from the MCOR (under the floor and connected to a linkage from the pedal) and jump out the connector with a paper clip or a small piece of wire. It will be a blue wire and green wire connector. If it runs correctly with the jumper in place, your MCOR MS has failed. Get one here https://www.revolutiongolfcars.com/mcors

[Sergio]

What has been described is virtually impossible unless the cart was miswired from the start.

Make sure the Motor Armature (A1 and A2) cables are connected to B+ and M- at the Controller.

If someone has the M- cable connected to B-, once the Solenoid was stuck and there was a little movement of the wheel to break the inertia, there would be enough residual magnetic flux in the Field winding to turn the motor into a high speed with virtually no torque device.