Electrical Fault when turning high beam on

What you are describing is loose or dirty battery cable connections. Start by removing the negative cable, then the positive one. That order is important only because if you slip with the wrench and it touches anything metal on the car and the negative battery post at the same time, nothing will happen. If you remove the positive cable first and the wrench touches something metal at the same time, you'll have sparks like you have never seen before. The wrench can get hot enough to melt and bend under its own weight.

Once both cables are removed, use a wire brush to clean the mating surfaces of the clamps and the battery posts. You can use sandpaper too. They also make special wire brushes for this that work real well. You can find them at any hardware store, auto parts store, Walmart, etc. Once everything is shined up, reattach the positive cable first and tighten the bolt, then reattach the negative cable.

Note that if you have a lot of corrosion around the battery posts that looks like cauliflower, that is a sure sign the battery is going to fail within the next six months. The installer will also clean the cables when he replaces the battery at that time. If you do not see a lot of corrosion buildup, but the battery posts are black instead of the normal gray, that is from air in contact with the lead, and that is from a loose connection that has been that way for a while. Those posts will be shiny silver when they are cleaned.

Please let us know what you find so it will help others.

Best, Ken

Yes, it could have ruined the battery, Refill it to see if it comes back to life, if not you mat need to replace it, here is a guide that will help you.

https://www.2carpros.com/articles/replacing-car-battery

Please let us know what you find.

Best, Ken

I'll go one step further. When a portion of the lead plates becomes dry, it's not coming back. Also, the current that goes through one cell is the same as what goes through every cell, so why did the water boil completely out of only one cell? That's because a higher percentage of lead has flaked off the plates in that cell, which can't be avoided, so the current had less lead to store electrons in. That makes what lead is left get hotter, hence the boiled-out water. The lack of water did the battery in, but the lack of water was caused by a battery that was about to fail, so don't beat yourself up over neglecting it. Pop a new battery in there, then just to double-check, have the charging system tested, particularly for charging system voltage, or you can do that yourself with an inexpensive digital voltmeter. Measure the battery voltage with the engine running. It must be between 13.75 and 14.75 volts.