EV charging problems

Hi all - new poster but I have lurked and learned for a couple of years now.

I am getting the following symptoms on my 2011 ranger with 600 hrs.
1) when plugged in to ac, charger light on dash stays dark
2) when key turned, no lights on dash, charge meter shows half charge, hour meter on as normal
3) testing individual cells with a multimeter shows all at around 13v and for good measure I have charged them individually with a separate charger
4) when connected to an delta q quik charger shows two flashes - battery voltage out of spec

Any ideas? I am confused as all of the batteries seem to have decent voltage on them. Could some or all of them be disconnected somehow?

Thanks so much. Tom