2008 RXV "AC Over Current"

[nickdalzell1]

This one has me in for a loop, and i'm certain it's our tiny little shop not being tooled correctly for proper diagnosis of these 'fancy' cars.

2008 Danahar RXV EZGO. This is a fault I've NEVER seen before. number 8972 AC Over Current. Diagnostic manual has me testing wiring (OK) and ohms between motor wires, all normal. I noticed the solenoid was red hot (as in it'd burn you touching it) after the last test drive, where the car basically did the RXV way of letting you know something was wrong--by throwing driver through windshield. It never did it to me and runs fine when i'm on it.

Brake ain't the issue, it isn't even warm. I replaced the solenoid and it is still randomly doing this. I've no idea how to diagnose this car other than throwing random parts at it until something works. I have no oscilloscope, no tools other than a simple multi meter and danahar handheld. The handheld is not doing anything that helps me. Neither is the manual.

Advice on proper diagnostic tooling is also needed--The boss is asking what i need to properly do this and what tools are best. This may be the only chance i have at finally properly setting this shop up. anything helps!

[buckeyejudge]

I had the same cart, and I gotta say, I'd prefer a check engine light or an annoying beep, as opposed to being thrown through the windshield. Interested to see what you find out.

Sent from my LG-M430 using Tapatalk

[cgtech]

Is the fault recurring? If so, is battery voltage dropping when the fault occurs? I have seen failing controllers do this. I can count actual failed RXV motors on zero fingers. (With the exception of one that had massive corrosion intrusion, not a real "motor failure" in my book, that's abuse and zero maintenance).

[nickdalzell1]

I'm at the point where it may be controller, or motor. Not sure which (and don't like being wrong and having to go through the time of undoing what i did). The tech at EZGO we called was assuming it might be the motor encoder but the symptom doesn't match.

When a motor encoder goes out, the car runs at like half a MPH and grinds badly. This one runs perfectly fine and just shuts down and locks up. Each shut down it throws the 8972 AC Over Current code. I've never seen this code at all in my life. This is first time.

Batteries were full of corrosion and cable on rear battery fell apart in my hand, and i thought i had an AHA! moment, but new cables and cleaning the terminals didn't accomplish anything. The red hot solenoid was another AHA! moment that was short-lived.

I hate throwing parts at a car. We don't have the proper diagnostic tools (well, the OEM handset was a godsend on the curtis variants!). I have no means to program the QE chargers for battery profiles, and have no means to properly rule out a bad motor encoder/speed sensor other than by symptom.

We recently got a very expensive battery testing station and the batteries test out perfectly fine under load. No one battery is falling out. Batteries are 2017 US Batteries.

The only two (TWO) RXV AC Motors i replaced were as follows: one guy towed dead RXV without putting in TOW (and he removed brake) and cooked the motor and controller, definite smell on both.

The other was a customer who lifted his car and had a 900lb toolbox on it and had car programmed to 20 MPH. He kept having a 'motor over temp' fault. We replaced his motor to satisfy his complaint, even though his overloading the car was the real problem.

Lately we have been having PowerDrive 3 chargers go bad where they click but no amps, no hum, no vibration at all, like it's stone dead. I can't fix these for the life of me. We try putting diode boards in and nothing works. Our working PowerDrive 3 chargers will charge these cars in question so the OBC ain't the part that failed. I need to know how to properly diagnose these as it's not nearly as easy as a dead PowerDrive 2.

[cgtech]

I have the Delta-q programmer, and I can't program QE or SC-48 chargers either, only QuiQ. The shutdown situation may actually be an encoder fault, causing the controller to go "full force" stopping, throwing the code.

[nickdalzell1]

I've never seen an encoder do that though. They've always failed all at once. But it's something i'll look at. Wish i knew how to properly test one. We don't have an oscilloscope nor would i know how one works.

I have read and dealt with US Batteries not fully charging with a QE because it's programmed for Trojans. Maybe Bob Boyce knows? Personally I would sell the cars with a good charger and toss every QE that came in, but customers are too cheap to pay $400 more on a car even if it's less trouble.

In my experience, an RXV will go 'full force' for any fault, regardless of severity. bad solenoid, bad battery, bad microswitch in pedal group, too many keychains on a key ring, etc.

[cgtech]

Cheap (less than $30) 'scopes can be had from the usual eBay scumbags. They have 2 really nice features- 1, they are portable, powered by a 9v battery. 2, they are so cheap, who cares if it falls off & gets run over. They aren't the highest quality, with the highest resolution, but are more than good enough to watch an encoder signal.

[nickdalzell1]

BTW it ended up being a speed sensor. It had one of those newer style inductive versions that are stuck in the motor with a T30 torx screw, much like the Curtis variants. Thank goodness it didn't end up requiring pulling the motor because if it was one of those Encoders (and it ended up not being the part that failed) that would have been a huge waste of time!

CG, sadly my boss doesn't trust Ebay. She will go through Amazon though.

Where on this forum would be the appropriate place to ask general questions (like about tools, golf car general discussion, etc)? The off topic forum description mentions not talking about golf car related stuff but there's tons of non-specific stuff that wouldn't properly fit in say an Ezgo or Club Car forum.