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Discussion Starter · #1 ·
was checking battery voltage on my daughters '04 accent the other day with my dmm and got a reading of 12.4 then started the car and got the same reading. Thinking a bad alternator I changed it out and put on a new one...still same reading at the battery. Every other car I check I get an alternator output reading at the battery. Could the voltage regulator be sepparate from the alt.and maybe that is the problem?
 

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Regulator is built-in.
The alternator won't begin charging unless it receives "excitation" voltage to set up the initial magnetism in the rotor. See attached snippet.

Excitation is provided by dash Fuse #2 and the "pre-excitation resistor" inside the engine fusebox.

With key in the On (RUN) position, measure voltage from Ground to the resistor. One side should read 12V and the other a bit less.
It may be worth verifying that there is voltage at the "LAMP" terminal (#2) on the alternator as well.

Also, check that the alternator "SENSE" terminal (#1) has 12V.

Let us know what you find.

Jim

Be sure to register for FREE access to the Hyundai on-line Shop Manuals. See Sticky.
 

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Discussion Starter · #3 ·
Thanks Jim for the info and the diagrams.I'll check these circuits the next time I get to the car-she lives in a different town... Although yesterday I got to look at it for a minute and found the wire that is bolted to the positive battery terminal was very loose! This is the wire that goes to the fuse box and alternator fuse I believe. Took it off and cleaned it and retightend---hopefully this is the culprit. Will let you know. Thanks again
 
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