Hey Scotty, I have a 2002 Ford F250 XLT 4x4 v8 5.4L Engine
I put in a new alternator because the old one was not charging my battery. Well the new one is not charging the battery either. I can crank it up with a jump and as long as the cables are on it, its all good, but after taking the cables off, i can see the battery on a meter discharging. I took the alternator to the auto store and they tested it and it is working..
Have no idea what it can be man.. cable looks ok.. I can test the ground but could it be a fuse or maybe the connector's return is not good?.. What do you think and if any other thing for me to check???
Did you get the battery tested?
It could be a bad connection somewhere. measure voltage drop between:
- engine block and batt neg.
- alt pos stud and batt pos (could be a blown fusible link)
- if it's not those, then the alt isn't getting good field signal from computer.
Thank you. I tested the Positive wire that goes from the ALT connector to the positive Post of battery to see if ground is good and it is.. so that tells me Engine block and batt neg are ok.. I looked around for possible fusible link, but have not spotted any .. "Yet".. I did think of a possible computer issue due to the voltage regulator being part of the PCM, but the fusible link came to mind first due to not getting a "Battery" light at all on the dash.. I am also thinking of any kind of issue that may come from ignition switch, even though the engine does start when turned but .. of course no charging present... it starts while being jumped ...
Back up!
I tested the Positive wire that goes from the ALT connector to the positive Post of battery to see if ground is good and it is.
Tested how exactly? Ground is negative. Positive wires should never be connected to ground.
And you still need to test the battery.