voltage regulator, alternator or battery
02-02-2018, 08:14 PM
#1
Newbie
Thread Starter
voltage regulator, alternator or battery
Hello everybody.
I took my xj to get the battery checked and it came back as "voltage regulator failed", I replaced the alternator and battery and I still get the same thing. how can I fix that. should I get an external voltage regulator? any information helps.
thanks in advance.
I took my xj to get the battery checked and it came back as "voltage regulator failed", I replaced the alternator and battery and I still get the same thing. how can I fix that. should I get an external voltage regulator? any information helps.
thanks in advance.
02-03-2018, 07:10 PM
#2
CF Veteran
The voltage regulator is in your ECM, and this part of it is known to fail and the rest be just fine. You can try an external regulator or you can get yourself another ECM
02-08-2018, 05:38 PM
#3
Newbie
Thread Starter
New voltage regulator
so i got a voltage regulator, it goes conected directly to the battery. Nothing changed. My battery stays at 12. 37 v and when i rev it goes down then up. When i turn on my light bar, volts start decreasing even when the car is running. My light bar is conected directly to the battery, i bypassed the relay and fuze, does that matter?
02-08-2018, 07:12 PM
#4
CF Veteran
Bypassing the relay and fuse for the light bar would not be the issue (if there is one). The more important question would be whether the light bar was on, or off, during the test. I'll assume that it was off.
Those auto parts store tests don't really have the ability to test your PCM voltage regulator. At least not in a way that is consistent with the FSM guidance for testing it. Most likely, those store testers increase then decrease the amperage load on the system in steps, and check the voltage at each step to see if it stays within a certain percentage of the voltage before that portion of the test was initiated.
Without the new external regulator in the picture. Measuring at the battery posts, can you tell us what the system voltage is -without- the vehicle running, then what the system voltage is -with- the vehicle running? That would be a good place to start.
Those auto parts store tests don't really have the ability to test your PCM voltage regulator. At least not in a way that is consistent with the FSM guidance for testing it. Most likely, those store testers increase then decrease the amperage load on the system in steps, and check the voltage at each step to see if it stays within a certain percentage of the voltage before that portion of the test was initiated.
Without the new external regulator in the picture. Measuring at the battery posts, can you tell us what the system voltage is -without- the vehicle running, then what the system voltage is -with- the vehicle running? That would be a good place to start.
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