Were do I find a wiring diagram for this battery charger merits model number 24/4?

If this is when the charger is plugged into the chair, the chair goes into inhibited mode so you cant drive away towing the charger with you. A safety feature.

Batteries don't like just sitting around, they like to cycle that is discharge and charge. Yes you most likely need new batteries. Long slow charging is best for batteries, I would give them 8 to 12hrs.

hi, okay so you got a onboard charger ? right there should fuses fitted to either on of the three wires coming out of the charger ? unless the charger is itself is faulty ?

Regards
Rob

Make sure the connections are on correctly!

I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_bcbb89783b08c489

Flash Code 2 indicates that the voltage is too high or too low. Check batteries and cable connections. Charge the batteries. If this fault occurs during battery charging, the charger is defective or not adjusted correctly. Empty batteries will charge. Dead batteries will not normally charge.

You had better recheck your connections because the batteries are polarity reversed

Blue Positive Brown negative, Yellow with green stripe is additional ground. many people are trying to use the 2904JT charger for a 24 volt charger for other things. I am using mine on an e bike that has 4 12 volt batteries. I charge them 2 at a time and it works well. It only shows voltage when the batteries are partially charged. Some kind of safety feature to keep you from charging a shorted battery. No schematics available, I took my chances and verified the Blue wire is positive. lol Good luck with you project or re wire. : )

sounds like the engager (paddle assy.) needs to be replaced