New alternator, new battery, won't charge
Asked by Guru1HBFG Sep 10, 2019 at 02:54 PM about the 2003 Ford Explorer XLS Sport V6
Question type: Maintenance & Repair
Just installed a new alternator and battery as they were
both bad (bench tested both). When the truck is running I
am getting ~12 V to the alternator. The dash guage for the
battery stays at the bottom line. When the truck is running
and the battery is disconnected the truck dies. My current
diagnosis is a wiring problem unless this runs through a
fuse somewhere and that is cutting the connection (Idk
where) preventing the alternator from starting. Video I have
found gives me a workaround that can fix this problem
without me having to pull half the motor apart to fix the
wiring. Before I jerry rig this fix, any thoughts or
suggestions on something I may have missed?
https://youtu.be/VYkTdnwQKJ4
6 Answers
Sounds like your alt is not functioning. That would explain why your battery is being discharged. Could you have incorrectly routed the serpentine belt around the alt pulley?
What is the voltage at the battery when the truck is running using a multimeter?
My car shows 14.5V when running (12.5V when turned off).
Then your alternator is functioning properly when the engine is running with 14.5 volts. A 12.5 volt battery indicates the battery is fully charged.
Also. I had a 2003 XLS. The problem could be in the instrument cluster if the battery indicator is not moving at all. There are no serviceable parts inside the cluster and if there is a problem the entire cluster needs to be changed. There is one large cluster plug which connects with the instruments. Knowing which terminal corresponds to battery gauge is impossible without a diagram. You could purchase an independent voltage gauge/meter to mount inside the vehicle for continuous monitoring. But you basically did the same thing with your hand held meter when you determined the alternator was charging at 14.5 volts.
OJ, I answered the person starting this thread. I am not the originator and the car used is not his. He wanted to know what voltage level to expect in a "engine running" state so he could compare to his car, presumably to verify his alternator was working. He still needs to troubleshoot his problem.
