Electronics neophite, but understand electricity fairly well.

Late 90's vintage, 24v.

1st sign of problems when I'd hit a sharp bump, it would cut out completely. But cycling key would get it going.
Now it won't run at all. Batteries charged. Can hear the relays kick in. Got stuck in a field, may have fried something, but circuit breaker is closed.

Has 2 pots - one a throttle pot, the other a speed limiter pot.

Very basic controls - no lights, etc. Couple of analog volt meters (main voltage and charger voltage).
Need some guidance. Thanks......Pics... (unused spade connectors for some add-ons -- lights maybe, not used)

 

First thing I would do in view of your description is look for dry joints especially on the relays and any other heavy components. Re-solder any suspect looking joints. It could also be intermittent relays, they do wear out or get contacts stuck once the plating of the contacts is worn. this is due to micro arc welding due to sparking. A good thwack with the handle of a screwdriver may temporarily free them, but replacement is the best solution.
The accumulators also can go open circuit, which will only show up if you try and connect a load such as a bulb across them while measuring the voltage. With no load applied, the meter may well show voltage if its one of the intercell bridges that has come loose but is covered in the electrolyte. the voltage will collapse under load. This fault is common with off road motorcycle batteries due to the constant vibration and mechanical shock.

 

Thanks reckless --
Guess I'll ohm the pots 1st. One looks like a 25k, the other a 5k, I'm guessing.

There are 4 ice-cube relays total -- 3 soldered to board, 1 wired with connectors. I'm making an assumption that 1 is for reverse (always slow speed) and 3 for forward.

I can find the relays and pots on the internet. But just needed a bit of direction before I break out the soldering iron....

 

You may need to use a magnifying glass to spot any bad contacts or joints, also look at the multipin plugs and sockets, especially if there is any sign of heating due to poor joints. It does sound like an intermittent connection somewhere.

 

The only one I fixed had corrosion in a connector from the front controls to the brain board.

 

But just needed a bit of direction before I break out the soldering iron....

I'd suggest reflowing the solder on any connection you think is carrying high current. I lost headlights twice in an old BMW and both times it was solder joints in the Lamp Control Module that had fractured from temperature cycling.

The only mobility scooter repair I've done was for frayed wires going into the steering post resulting is loss of power.

 

You mentioned cycling the key would sometimes resolve the issue. It's worth checking out the key switch, especially if it's got more than 2 wires.

 

Thanks for the suggestions, all.
Haven't had time to mess with it much -- luckily, I have a backup.
All the hi-amp solder points look good. I'll get on it this weekend....