Another Reed Switch bypass

[JohnnieB]

Originally Posted by Skydivertony

Did this and the pot is working as it should. I suspect the motor and here is why...
With all the wires connected to everything

1. I hook volt meter between B+ and A2
Key on, pedal depressed - 0 volts

2. I take the (traced red) A2 wire off of the controller and hook everything else back up (eliminating the motor from the circuit, I believe)
Key on, pedal depressed - 36 volts between B+ and A2

1. With no amps flowing, those two points would have the same voltage on them, thus a 0V reading.

2. Without the A2 cable, you are measuring across an open, so you measure applied voltage.

To check the high amp series loop, connect your DVM's negative test lead to the controller's B- terminal and the positive test lead to the controller's M- terminal.

When pedal is pushed just far enough to make solenoid click, you should read full battery pack voltage and as pedal is slowly pressed to the floor, the voltage should smoothly decrease to 0V. (The electronic valve is physically located between B- and M- and effectively goes from an open to a short as pedal is pushed)

If you don't get full pack voltage when solenoid first clicks, go searching for it with the positive test lead. The F/R switch contacts are the most likely suspects, but might be motor brushes or a bad cable or connection.

If you do get pack voltage and it doesn't decrease to 0V as pedal is pushed, it is either the controller or the throttle and you've already checked the throttle.

[Skydivertony]

Originally Posted by JohnnieB

1. With no amps flowing, those two points would have the same voltage on them, thus a 0V reading.

2. Without the A2 cable, you are measuring across an open, so you measure applied voltage.

To check the high amp series loop, connect your DVM's negative test lead to the controller's B- terminal and the positive test lead to the controller's M- terminal.

When pedal is pushed just far enough to make solenoid click, you should read full battery pack voltage and as pedal is slowly pressed to the floor, the voltage should smoothly decrease to 0V. (The electronic valve is physically located between B- and M- and effectively goes from an open to a short as pedal is pushed)

Okay I will check that today. But between me and the last guy who worked on it ... the F/R switch and the controller were both replaced with new ones. I even put the old F/R switch back on it and still just the solenoid click.

If you don't get full pack voltage when solenoid first clicks, go searching for it with the positive test lead. The F/R switch contacts are the most likely suspects, but might be motor brushes or a bad cable or connection.

If you do get pack voltage and it doesn't decrease to 0V as pedal is pushed, it is either the controller or the throttle and you've already checked the throttle.

Okay, I will look at that today. But between me and the last guy who worked on it, the F/R switch and the controller have both been replaced with new ones. I even put the old F/R switch back on it (the other guy changed it) and still just get a solenoid click. Thanks for all the help too.

[JohnnieB]

Originally Posted by Skydivertony

Okay, I will look at that today. But between me and the last guy who worked on it, the F/R switch and the controller have both been replaced with new ones. I even put the old F/R switch back on it (the other guy changed it) and still just get a solenoid click. Thanks for all the help too.

New does not equal good.

If an new F/R is good, but not positioned correctly, it won't work right. The mounting holes are oblong and the bracket needs to be adjusted horizontally until the cam rotates into the mechanical stops in both F and in R.

The tricky part about troubleshooting EZGO golf cart DC drive systems is B+ is connected directly to the motor and the controller controls B-, which is the opposite of the way most variable speed DC motors are controlled.

The nice thing is the high amp circuit is effectively a single current path made up from 13 cables with 26 connectors, 3 sets of contacts, some MOSFETs and the motor's armature and stator windings, all in a series loop.

In other words, you are troubleshooting a single wire with several lumps in it and all you have to do is find out which lumps isn't passing the amps to the next one.

[Skydivertony]

Originally Posted by JohnnieB

1.
To check the high amp series loop, connect your DVM's negative test lead to the controller's B- terminal and the positive test lead to the controller's M- terminal.

When pedal is pushed just far enough to make solenoid click, you should read full battery pack voltage and as pedal is slowly pressed to the floor, the voltage should smoothly decrease to 0V. (The electronic valve is physically located between B- and M- and effectively goes from an open to a short as pedal is pushed)

If you don't get full pack voltage when solenoid first clicks, go searching for it with the positive test lead. The F/R switch contacts are the most likely suspects, but might be motor brushes or a bad cable or connection.

If you do get pack voltage and it doesn't decrease to 0V as pedal is pushed, it is either the controller or the throttle and you've already checked the throttle.

Hooked up meter like you said. Pushed pedal until solenoid click. 13.2 volts. Stays the same with the pedal all the way to floor. Let the pedal all the way back up, and after about 20 seconds the voltage slowly bleeds down.
I will try to find the voltage.

[Skydivertony]

In forward, at solenoid click, I have 37 volts at A and B on the F/R switch and 13. volts at D and C. And in reverse I have 37 volts on A and D and 13 volts on C and B.
Is there anyway that I can test the motor, or eliminate it from the equation?

[JohnnieB]

Attached drawing is how to test a series wound motor.

[Skydivertony]

Originally Posted by JohnnieB

Attached drawing is how to test a series wound motor.

Should it run on 18 volts? Because it doesn't

I put the switch on the other side, which I am sure it doesn't matter.
18 volts at S2 - A1 and no go. I think the studs inside the motor turned when the last guy took the cables off to clean the connections.
Triple checked my connections. Will order a motor.
And I ohm tested the new F/R switch and it is bad. The contacts are crooked and sitting up on the plastic part of the switch, instead of making a good contact.
And I'll attach a pic of the motor. Tells you how to test it. I never looked

[Skydivertony]

Turned out to be the motor. Thanks for all the help. This thread should help some people out.
I work on a lot of golf carts but this is my first electric one. Boy can they get expensive, lol.

[sthreatt]

Originally Posted by Skydivertony

Should it run on 18 volts? Because it doesn't

Actually, with the wheels off of the floor and hooked up as shown it should run off of 12 volts to test.