My roommate and I were going to go out in the car for the first time in 3-4 weeks, but it wouldn’t start and said there was no key detected in the vehicle (it is a Dune edition that just has a start button). So my roommate (in the passenger seat) looked in the manual and on their phone and we tried some of the suggestions, like pressing the start button with key fob, or holding the key fob next to the steering wheel while pressing start. But then one time all the lights came on - the dash lights, a lot of the emergency icon lights, the lights on the door buttons… except the car still wasn’t on, and now the lights won’t go off, and the key fobs won’t work to lock/unlock the doors anymore. Even the headlights and brake lights are on. My roommate thinks that the battery died and when we tried too hard to turn it on, something in the electrical system got damaged. Any insight would be greatly appreciated! I really really hope it isn’t as bad as I think it is!
Update: The headlights and brake lights have turned off now, but I don’t know if that’s good or bad.
Update 2: More lights have turned off, but the dash lights are still on.
Today’s cars can be quirky when the battery voltage gets low. As others have said, charge the battery (preferably with a battery charger instead of your alternator) and see what happens after that. If you’re going to leave the car for long periods of time, you should consider getting a battery maintainer.
What does the OM say about removing and replacing the battery? Anything need to be “reset” when a fully charged battery is hooked up?
You could hook up a battery charger, if you can. Or remove the battery and have it tested and maybe put on a charger at a repair place. Or, esp. if it’s more than 4 years old, just get a new one.
One of the things I wanted to do with the article was list all of the vehicle applications that have known battery disconnect issues. Unfortunately, I have never found such a list. Most vehicle owners manuals don’t offer any precautions about disconnecting or replacing the battery. There may be some cautions in the factory service literature, but it is often hard to find even if you know where to look for it.
SPECIFIC VEHICLE BATTERY PROBLEMS
BMW, Audi & VW (various models) Disconnecting the battery requires numerous module relearn procedures which can take up to several hours with a factory scan tool
It may be too late for this battery, if it is severely discharged, but any need for “relearning” might be avoided if a small battery remains attached to the battery cables while the car’s battery is removed. A 9V battery can be adequate.