Battery indicator light is ON
Junior User
Joined: Feb 2004
Posts: 82
Likes: 0
From: Richmond, VA
Yeah I would have to say most commonly it is the alternator but I have also seen a problem with one of the wires on the back of the alternator coming loose in the connector. My old 2000 f350 psd went through 7 or 8 alternators
New User
Joined: Sep 2004
Posts: 8
Likes: 0
Just went through this on my 99, replaced the alternator still had the problem, checked all connectors, they looked good, then replaced with another alternator and the problem was resolved. The first replacement alternator was charging, but the battery light was still on, the problem with the first replacement alternator must have been in the internal sensor circuits. I guess rebuilt alternators have a high failure rate out of the box.
to check where the problem is
1. check voltage with truck running at the batteries, if it is a diesel wait until the glow plugs shut off, should have higher than 14 volt if not replace alt
2. if charging is ok check voltage on the connector on top of the alt
left wire should be 12 v if not check wiring to the connector
right wire should be approx 1.5 with key on engine not running and 12v with engine running if no 1.5v check wiring to connector, if no 12v while running bad alternator
3. if you do not get 12 v to the left connector check fuse 7 under the hood, it is a 10amp fuse
to test the connector it must be plugged into the alt, just push your meter probes into the top of the connector
good luck
to check where the problem is
1. check voltage with truck running at the batteries, if it is a diesel wait until the glow plugs shut off, should have higher than 14 volt if not replace alt
2. if charging is ok check voltage on the connector on top of the alt
left wire should be 12 v if not check wiring to the connector
right wire should be approx 1.5 with key on engine not running and 12v with engine running if no 1.5v check wiring to connector, if no 12v while running bad alternator
3. if you do not get 12 v to the left connector check fuse 7 under the hood, it is a 10amp fuse
to test the connector it must be plugged into the alt, just push your meter probes into the top of the connector
good luck
New User
Joined: Jan 2010
Posts: 9
Likes: 0
battery indicator
My 2005 Ranger (3.0) has a similar problem. Usually at 2g rpms. Got home on battery power on one occasion. Other than that the problem is sporatic. 18 miles to work. Light stays on last 5m or so @ hiway speed. Tested Alt. it draws from battery, but settles down @ 12.34 volts. T. pulley and S. belt seem to be good.
New User
Joined: Jan 2010
Posts: 9
Likes: 0
Makes sense not88. Will re-test. I too have bad luck w/ rebuilt alts. Went through 4 of them B4 I got a good 1. Lots of time wasted on that project.
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New User
Joined: Jul 2013
Posts: 1
Likes: 0
From: Alberta , canada
battery light is on full time , and it is over charging main battery, corrodes up every 2-3 weeks, 2004 F350 - 6l
any ideas?
any ideas?
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Cargo Master
Joined: Jan 2012
Posts: 3,053
Likes: 21
From: Pittsburgh, PA
Just for the record, alternators can be rebuilt. Typically, there is a voltage regulator on the back and underneath that is the brush assembly. If you alternator spins true and the bearings are fine, save some cash and just replace the regulator and the brushes.
Regulator:
More Information for STANDARD MOTOR PRODUCTS VR455
Brush Assembly:
BWD Alternator Brush Set X581: Choose the best Alternator/Generator Brush Parts at Advance Auto Parts
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