2009 RXV Brake Lights on and Accelerator Unresponsive

[Fred H]

Good morning everyone.

It has been a while since I was last posting but work has continued on my 2009 RXV cart. I have recently run into a problem that I have been troubleshooting and have come to a "brick wall" on what to do next. Sorry in advance for the length of this post, but I wanted to provide all the information I have to date;

2009 EZGO RXV
Serial Number 5051333
Date D2309 ( I haven't found a way to verify the date the than the 09 last two digits. The date seems critical to determining which wiring schematic to use)

Situation: While preparing for Hurricane Ian, I attempted to add a 12-volt cigarette lighter socket to allow USB charging from my golf cart batteries in the event of an extended power outage. I pulled up the cup holder and tapped into the brown hot lead going to the emergency flasher relay (my cart has the EZGO turn signal/flasher kit installed that interfaces with the factory 8 pin connector). I was looking for a suitable ground wire as the blue common to the flasher seemed to be giving me intermittent charging voltage to the lighter socket. Assuming this was not a suitable ground, I looked for a black ground wire in the harness going to the instrument panel. I checked continuity to ground and tapped into a black wire. I may have shorted the brown hot to the black ground briefly when I was messing with the socket. Bottom line is the black lead went to the SOC meter connection when I traced it back.

The cart is now inoperative and exhibiting the following;

When I power the cart, the brake lights stay on in all three key positions

The solenoid kicks on, jerks, and kicks off (two clicks)

The run/tow switch works as it should, releasing the brake and allowing the cart to be moved

The SOC meter lit but did not respond initially. When I took power off the controller, drained residual, and reconnected power, the SOC meter started working normally. The accelerator pedal is still not responsive.

The reverse buzzer works

The run plug connections have been checked.

All four fuses attached to the run/tow switch cover have been checked

I am concerned where to go from here. I have a Fluke DVM I’ve been using but do not know what I may still be able to check. My controller is the original Danaher and worked fine before this situation happened.

I do have a Curtis 2Five controller and associated interface cables and pin to pin connector that I purchased to perform a future controller changeout. I hesitate to make the change and unknowingly connect it to some fault I’ve created and damage the new controller.

I done hours of searches to try to find out what might be the cause and would appreciate any additional guidance anyone can provide. I would like to continue to use my existing Danaher controller setup if it is still salvageable or if there is some individual component diagnosis and changeout I can make to resolve the problem.

Best Regards,

Fred

[Fred H]

With additional troubleshooting, it looks like I accidentally applied 12 volts to the #4 pin Danaher 5 volt controller ground.

I've been troubleshooting circuits and so far, in addition to the above post, Ive verified the charger connection and the circuit to the SOC meter.

Checking the brake relay circuit, with the key on and relay removed, I get .5 volts across the red and purple wires, terminal 85 and 86. When I depress the brake pedal, voltage goes to 48 volts, not the 12-15 volts I am supposed to see according the the RXV troubleshooting guide.

Is there any way to tell if the controller is bad using a digital VOM? I do not have access to a Danaher handheld or a known good controller.

I appreciate any guidance you can provide.

[kgsc]

Brake relay should see 24 volts to activate the coil. If you are seeing 48 that isn’t good. Also if you shorted the 5 volt circuit it probably trashed the mosfet in the controller.

[Volt_Ampere]

Sounds like new controller time.

[Fred H]

Thanks KGSC,

What is confusing to me is that my brake relay does have a 24 volt coil but my Accessory harness one line diagram in the manual shows a straight 48 volts coming to the red lead at Terminal 85 of the brake relay.

[kgsc]

That is correct.. Danaher is playing a few tricks here and when it activates the circuit it is providing a ground that is restricted so it equates to a 24 volt circuit. Not sure why but that is the deal.

[Fred H]

Thanks KGSC.

I figure the only way a 24 volt relay works with a 48 volt feed is that the controller purple "ground" is actually at a 24 volt potential to make everything work.

[Fred H]

Last night I installed a replacement Danaher controller I purchased from a private party on Facebook. The diagnosis of a bad controller was correct and the cart is now back up and running.

I want to thank both those that posted replies here and thru private messages for your assistance in helping me troubleshoot this problem.

The only thing I have left to do is to determine if the Freedom mode is unlocked. The previous owner did not know the status.

If Freedom mode is enabled, is there a typical speed I should be reaching on 20.5 inch tires?

Again, thank you all for your help :-)

[kgsc]

If freedom mode is enabled it is supposed to run 19.5mph on 18” tires so with yours you should be low 20s.

[ojo]

Fred, with my 20.5" tires i got exactely 22.6 mph with freedom mode enabled. There is a acceleration setting also ( low/mid/high )