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Alternator's not charging

my 92 XJ

NAXJA Forum User
Location
Rochester,N.H.
I have a 92 XJ,and it's not charging.I have a new alternator and a new battery.I even swaped out the new alternator and the battery...again.
Now here is some more info.I had to change the computer and I swaped it with a 91 XJ computer and it had all of the same options as mine,but the numbers were different.Would that cause the issue or is there a relay or something that would keep it from charging? I have checked and cleaned all of the grounds and leads. Thanks for the help
 
Well, the 91+ XJs have the Nippon Denso alternator and charging is controlled by the PCM.

Did you have the no charging problem BEFORE or after the PCM swap?
 
I don't know.I bought it and it needed a computer.That's why I changed it. I still have the computer that came out of it,but one of the prong things broke off.I think thats why it needed one.
 
Ok, so bear with me on this, and if I underestimate your skills no offense intended.

You say it isn't charging. Is this because it isn't charging or the battery keeps ending up dead? They really aren't the same thing, necessarily.

So, question: if you attach a voltmeter to the battery at the terminals, start the engine, what doe the voltmeter read?
 
the battery while running,goes dead. Thats why I say it's not charging.The gauge stays just above the red and goes down from there.I haven't put a volt meter to it yet,I gave up for the day after I found this out. No offence taken
 
Have you checked the fusible link in the charging lead going from the alternator terminal to the Power Distribution Block which then connects thru another small cable to the battery positive lead ??
The fusible link may have blown.... You can check this for continuity using a VOM once you have disconnected the positive battery terminal and the lead to the alternator.
 
Have you checked the fusible link in the charging lead going from the alternator terminal to the ECM with then connects thru another wire to the battery positive lead ??
The fusible link may have blown.... You can check this for continuity using a VOM once you have disconnected the positive battery terminal and the lead to the alternator.

Continuity--good in life, good in electrical connections.

Also, what pin number is screwed up in the old PCM? Could be maybe it fouled the connector for the harness and that might be effecting the PCM's alternator control.

Edit: check the continuity as CharlesS said, and the volts between the terminals. Post back your results.
 
It was the 60 amp fuse in the fuse block on the pass. side fender. Thanks for the help guys!!

CharlesS gets the cookie for this one.

There are two 60 amp fuses that take the place of the earlier fusible link on the lead from the alternator.

Glad you got it.
 
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