battery's continue to die?
Fleet Mechanic
Joined: Dec 2015
Posts: 1,521
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From: Washington Coast
Unfortunately a lot of the people that are doing these test do not know what they are doing so they typically only look at one thing and that's the DC Volts output. The tester they use is like the fancy dancy electronic battery tester I used to use when I worked service trucks, worthless other than to tell you the battery had 12 volts but as soon as you put a load on it dead as a doornail. I only use one of the heavy duty load tester that actually puts a nice heavy load.
There is another test you can do with a multimeter, disconnect the charging wire to the battery from the post on the alternator and test for continuity in both directions, black to case with red to the post then black to the post with red to the case. If the diodes are bad you will be able to read continuity both directions, if good only in one. Most better quality DVMs have a diode tester as part of the resistance, looks kinda like a stick figure Christmas tree on it's side.
Yes you can put a larger amperage alternator on your truck without any modifications.
There is another test you can do with a multimeter, disconnect the charging wire to the battery from the post on the alternator and test for continuity in both directions, black to case with red to the post then black to the post with red to the case. If the diodes are bad you will be able to read continuity both directions, if good only in one. Most better quality DVMs have a diode tester as part of the resistance, looks kinda like a stick figure Christmas tree on it's side.
Yes you can put a larger amperage alternator on your truck without any modifications.
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Milwaukee1979F150
1999 - 2003 7.3L Power Stroke Diesel
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Dec 12, 2011 03:36 PM
