I have a 1993 jeep grand cherokee. its not charging. i've had the alternator and battery tested they're good. is it the voltage regulator? if so how do I change it? where is it? or can it be something else I can't think of?...

nothing wrong with the ECM unless it has the voltage regulator as part of the system
indicates faulty wiring and faulty alternator
have a load test done on the battery
have an auto electrician do a full charging system check
charging voltage should be 14.5-14.8 volts DC
battery voltage should be 12-13.5 volts dropping to 11 volts when cranking the engine
make sure that the drive belt tension is correct and the belt is in good condition

Check the coil see if ur getting power to it

The voltage regulator is in the PCM. If there is a problem with it, the PCM has to be replaced.

check voltage regulator

Have the alternator tested,remove it,and take it to the auto parts store,if it test good,replace the computer,the voltage regulator is in the computer.

When the vehicle is off and not running, the battery voltage should be 12.0 or higher. Ideally 12.7 @ 70 degrees F. While the vehicle is running, your voltage at the battery should read between 13.2 and 15.5 volts, this will tell you the alternator is suppling voltage to the battery for recharge, but the alternator will NEVER, EVER charge a full dead battery.

Based on what you noted, your system is not drawing too much, it is overcharging. Determine if you have an external regulator in your system (depends on alt. make and alternator design) Many of the Jeep systems have the voltage regulator as an integral part of the main computer. Likely it has failed. Also make sure that the charging system is properly grounded and the battery is fully charged and can undergo a load test without substantial voltage drop. If it cannot, it will over-work the alternator.

Only way you can get 15v anywhere is if the voltage regulator in the charging system has failed or your meter is inaccurate. Check meter against another known good one and if good, go for the regulator (can be in the computer or alternator depending upon which system is in yours) Nothing in the system should ever have more than normal battery voltage...12-14max.

Check battery voltage should be 12v or better with motor off. start engine read voltage again should be 12.9 or better and then turn all accessories on...voltage should be same or slight y less but best would be at least 13v let it idle and volts should not creep downward..
Volts should never be below 12 and never at 14 except for a brief time after startup. Turn engine off and disable ignition system, then check across battery while craqnking. Volts should not go below 9.5. If so, have batt charged and load tested. If good, replace starter. No valid electrical computer testing can be done without a fully charged battery.

Hello, with much satisfaction as of now, I am happy to say I have fixed this problem yesterday. I did so by continuing to read through these message boards, put certain ideas together and figure it out. We all know by now Jeep has ridiculous flaws, how a recall was never ordered, we may never know.
In any case, Jeep has a defective internal Security System. Once malfunctions begin to occur, it is all down hill from there. It cause Battery drainage even after changing battery. Simply remove the fuses for the security system. They are located on the pasanger side, on the right hand side of glove box there is a panel, remove it and find fuses # 6 and # 7. Take them out and Problem is solved.
I have tried everything from the wiring in door panel, wiring in foot panel and everything else that was suggested, It all finally came to an end one the fuses were removed. Good Luck and I hope this helps