Serpentine belt slipped and caused problems.

There's no way to diagnose the coolant leak over a computer without seeing it, but the battery light is on because the generator has stopped recharging the battery. It is run by that belt, so yes, you do not have a charging system problem. The belt is the cause of the battery light. The power steering pump is also driven by that belt so all that's needed is to get the belt back on.

You didn't say which engine you have. If the water pump is driven by that same belt, the engine will overheat within a few minutes and the coolant will expand and / or boil out of the reservoir. That will also be solved when the belt is reinstalled. On some engines the water pump is run by the timing belt so the engine would not overheat if the serpentine belt that you mentioned fails. In that case the coolant is a different issue and would likely be the cause of the serpentine belt slipping off. Reinstalling the belt in that case would not solve the coolant problem.

It's doubtful the belt problem was caused by a missing shield. Those are to keep fingers out of dangerous areas and to keep snow from getting impacted around the belt. The belt is going to get wet in rainy weather regardless if that shield is in place or not. There's a good chance a pulley is out of alignment or a spring-loaded tensioner pulley is loose or weak. The additional clues are a squeal from the belt when the engine is running. Or there's signs of fraying on one side of the belt.

Gotta diagnose exactly what is leaking to determine the cause. The typical things would be a gasket started to leak and the slippery coolant allowed the belt to slide off a pulley, the belt came off due to a misaligned pulley and the water pump is driven by the belt so after a couple of minutes the engine overheated and pushed expanding coolant into the reservoir where it overflowed, and the belt came off and slapped across a rubber radiator or heater hose repeatedly until it wore a hole in it.

It is also common for the water pump to develop play in the bearings. That lets the pulley wobble so the belt slips off, and the shaft wobbles away from the seal so it leaks coolant. That coolant leak would start out rather slow but the belt will suddenly pop off without warning when the wobble gets bad enough.

If the leak is rather significant, a pressure test will show where the coolant is sneaking out. If it's a real slow leak and the source isn't obvious, you can add a small bottle of dark purple dye to the coolant. After driving long enough for some coolant to leak out, you search with a black light. The dye will show up as a bright yellow stain. All auto parts stores will have the dye, and many borrow or rent tools. Those will have the black light.

Good to hear, please use 2CarPros anytime we are here to help.

Cheers, Ken