Truck wouldn't start yesterday. Tops of both batteries were wet. Driver's side battery plates were exposed and it also had significant corrosion on the positive terminal. I cleaned the batteries, terminals, and cables up and topped off the low battery with distilled water.

My question is, which PID should be watching to monitor for overcharging? My memory not so good, but I believe VBATT is battery voltage, FLP is voltage to the FICM I think, FMP Iis FICM voltage, then I have FVP, and I'm not sure what that is.

Thanks in advance.