EZGO RXV electric brake problem

[billmanley]

2008 RXV Electric with Danaher controller - Originally the resistor drain circuit was bad. I replaced it, and now a different (maybe related) problem has surfaced. The brake is dragging. I replaced the brake with the upgraded one. It still drags.
Voltage at the brake plug is 50.2 with the switch in N position and the run/tow in tow. Brake is released completely. Everything okay.

In F or R, voltage at brake drops to 12.9 and the brake drags (I have the cart up on jack stands).

I can't find any information on correct voltage. Is this correct. If not, what should it be? What components should I check/replace?
Someone please help before I lose my sanity.

[BobBoyce]

Originally Posted by billmanley

2008 RXV Electric with Danaher controller - Originally the resistor drain circuit was bad. I replaced it, and now a different (maybe related) problem has surfaced. The brake is dragging. I replaced the brake with the upgraded one. It still drags.
Voltage at the brake plug is 50.2 with the switch in N position and the run/tow in tow. Brake is released completely. Everything okay.

In F or R, voltage at brake drops to 12.9 and the brake drags (I have the cart up on jack stands).

I can't find any information on correct voltage. Is this correct. If not, what should it be? What components should I check/replace?
Someone please help before I lose my sanity.

The controller output for the motor brake PWMs (pulses rapidly) to give a lower average voltage to the motor brake coil to prevent overheating of the motor brake coil. Full voltage is only applied for a fraction of a second to pull it in, and the lower voltage holds it in.

There are a number of possibilities...
1. The FET (electronic switch) for the motor brake output could be failing.
2. Someone could have gone in with a programmer and set the Motor Brake PWM setting too low.
3. A bad connection in the wiring harness is causing excess resistance.
4. The Run Plug or Run Plug socket may have corrosion.

[cgtech]

The Danaher Rxv does not like the HD motor brake in my experience.

[BobBoyce]

I don't know the Danaher RXV well. I just figured it would be similar issues that the Curtis RXV has with motor brakes. Bill, cgtech knows those well and has a lot of experience with them.

[billmanley]

Originally Posted by BobBoyce

The controller output for the motor brake PWMs (pulses rapidly) to give a lower average voltage to the motor brake coil to prevent overheating of the motor brake coil. Full voltage is only applied for a fraction of a second to pull it in, and the lower voltage holds it in.

There are a number of possibilities...
1. The FET (electronic switch) for the motor brake output could be failing.
2. Someone could have gone in with a programmer and set the Motor Brake PWM setting too low.
3. A bad connection in the wiring harness is causing excess resistance.
4. The Run Plug or Run Plug socket may have corrosion.

Thanks for the info. However, the cart was running perfectly until the resistor drain module died. Is the FET inside the controller?
The voltage at the brake goes to 36V for an instant, when the accelerator is first pressed and then drops to 12V. There have been no programming changes. There is a relay in the circuit under the dash above the run plug socket. Could it cause the problem? If so, is there a way to test it? I can't find a part number for it in the service manual.

[billmanley]

Originally Posted by cgtech

The Danaher Rxv does not like the HD motor brake in my experience.

This is not the HD brake, just the upgrade one without the handle that is a replacement for the original. Should that be a problem?

[cgtech]

Not a problem. Who installed brake? Was it installed per directions (none in box, directions on the site)?

[billmanley]

Originally Posted by cgtech

Not a problem. Who installed brake? Was it installed per directions (none in box, directions on the site)?

I have the maintenance manual and followed the instructions for removal and installation, including cleaning, placing the run switch in tow, replacing and torqueing the bolts.

[cgtech]

Hmm, so it should be installed correctly.

[billmanley]

Originally Posted by cgtech

Hmm, so it should be installed correctly.

The original brake had the same problem after I replaced the resistor drain circuit. The original problem was the resistor drain. The cart had stopped working after the resistor heated. When I disconnected the black wire from the drain circuit, the cart would work, so I replaced the drain circuit.
I did remove the Danaher controller and its cover to visually inspect it for heat damage. I didn't see any sign of damage and re-installed it.

It's possible that the controller may have gone bad. However, I hate to replace it (it is rather expensive) if that is not the problem. I have considered buying the handheld diagnostic tool. There is no dealer/repair company that services RXV carts anywhere near us.

Would the 606215 handheld tool help in diagnosing this problem?