2003 Explorer alternator wont charge battery

[Dnvrbeer]

Hi. I had my 03 explorer sit idle for a while due to unemployment. I got it out of mothball. I put in a new battery. After a few days it died on me. I replaced the battery and alternator. The light on the dash is still on and if I run it, the battery drains down. I pulled both and had them tested and they are fine. Once I charge the battery, its stays charged like it should. Is the cable from the alternator to the battery bad, oranother issue? Guys at work have suggested a fuse, the cables or the GEM.

I can change parts but have no idea how to diagnose problems

 

[Number4]

If it sat for a period of time, with the old battery still connected, it's most likely that corrosion has worked its way down the positive cable. You may not be able to see it.

 

[Ziggycranston]

check the wire from battery to the alternator. I personally feel its a ground issue. Follow the ground from the battery to the engine. Even if it looks ok at the engine I would pull it and clean it with a wire brush.

Testing is easy if you have a volt/ohm meter. Set to ohms place one lead on battery ground and other on engine, it should read almost 0. Then check your positive side by placing one lead on positive battery post and other on back of alternator where the positive wire connects, its should read almost 0. If ether have high ohm readings you have a bad connection or bad cable.