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Voltage regulator

XJ16FW

NAXJA Forum User
Location
GA
Where is the voltage regulator on a 1989 XJ? I just replaced the alternator because the battery wasn't charging, but it is still not charging. I am hoping it might be the voltage regulator.
 
The voltage regulator is built into the Alternator.
The most likely issue is no power on the yellow wire hooked to the I/F stud on the alternator, with the ignition on.
Possible the fusible link on the red batt wire is burnt out.
How are checking the charging voltage? You can't really trust the dash gauge.
 
Inside the alternator. Check that the connector on the back of the alternator has voltage when the engine is running. Would suck if you replaced the alternator because of a wiring issue or blown fuse.
 
Inside the alternator. Check that the connector on the back of the alternator has voltage when the engine is running. Would suck if you replaced the alternator because of a wiring issue or blown fuse.
Yes it would :-(
 
The voltage regulator is built into the Alternator.
The most likely issue is no power on the yellow wire hooked to the I/F stud on the alternator, with the ignition on.
Possible the fusible link on the red batt wire is burnt out.
How are checking the charging voltage? You can't really trust the dash gauge.
I used a digital voltmeter at the battery terminals. I will check the wiring and fusible link.
 
You may want to check out Cruisers ground refreshing list. I did an ohm test on one of my alternator replacements when it charged poorly and found a significant resistance in the ground circuit. Not enough for no charge, but enough for a poor charge.
It's also possible something is wrong with your battery.
Be careful tightening the yellow (I/F) and tan (L) wire studs on the alternator, it's possible to spin the stud and break the connection internally. I clean the studs and wire rings then just snug them, then cover them with a finger full of grease or dielectric paste.
Sometimes the connection studs are marked differently, the important one is almost always I, F or I/F.
Not beyond the realm of possibilty, you got a new alternator that is faulty or a return/rebox that the parts guy gave you.
 
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