I have a 2002 Ranger, 4 cylinder, 2.3L motor. Let me start from the beginning when this whole problem started. My sisters Honda needed a jump start so I gave her one with my truck and then after that I noticed my batter gauge up in the H (red part). So I drove over to one of my brothers mechanic friend and by the time I got there the battery was already smelling like rotten eggs. And when the mechanic tested the voltage output from the alternator it was way up there around 270. He told me I needed a new alternator and battery. I had those replaced and then everything was smooth sailing after that. But about two days ago I washed the motor to clean up some residue from the sulfuric acid and as I was driving back home I noticed that battery meter jumping up and down. So from there I went through a processes that involved changing the alternator three times with three different new ones, everyone keeps thinking it's the alternator but it's not. After I changed the alternator for the first time the battery meter would just stay somewhere between the middle and L (low red). Shucks told me that the battery isn't getting any charge so it must be the alternator, but it's not.

If anyone knows what else could be the problem I would appreciate any input. I'm thinking maybe the wire harness needs to be replaced.

hi patch herd about this on a tv show here in the uk last week when jump starting a car never put both leads on the battery from the car you are jumping from one on the battery ( +) one on the engine if u put both leads to the battrey u end up as u have broken bat /alt sorry only ans half your question