Battery light came on in my 98 4 runner and went back off , drove it for a few days with it flashing on and off and different times will driving, now the light is on all the time, I tightened the belt becasue of a squealing noise , noise went away but the and the light went off but is now back on again ?

limited info generic answer seem to have a few things wrong ---driving through [puddle] may have or did damage electrical system like alternator which is not charging battery causing stall no start -but will need to test the battery alternator and electrical system ---also operating without oil water could also have gotten into engine and pretty much damage /destroy it need to inspect and check internals of engine

think its a computer system issue-its all connectd these days-even with the steering--disconnect batt then put it back after a minute-may clear up--------if not pull plug at computer clean it and replug a few times-----these reboots at times work------but u mite need to run a thuro diagnostic to see different voltages-go to a good mechanic not a dealer--a hand held scanner will not do this

Sounds like your alternater, get a multimeter set it to volts start the car then check the battery is getting 14 or over volts from the alternater to the battery , if your getting less than that it's not putting enough volts back to the battery to run the car with good luck colin

I would start with checking the computer for trouble codes.
Sounds like a bad connection in the dash wiring or key switch, but the trouble code might steer you in the right direction.

Check your belts make sure they are all there.

no not related by any means. P1684 Battery Disconnected Within Last 50 Starts

Welcome to the world of BMW's. return the car to the seller. you got a bad one. You got an electrical short draining the battery. Bring a blank check and sign it over to the dealer. They're going to have to run through the entire electrical system to find the short. That work alone is worth more than the a used up 2001 325i.

you should a button on right side of dash which opens boot

check for bad or lose connection at the battery

it's a default sensor to keep from blowing motor, you need to check your radiator for leaks. If that doesn't fix the problem , change your alternator. :)