I have been reading online and searching and have found similar threads about it, but some guys seem to run in circles on this issue.

When Im driving, my voltage gauge shows about 12-14 volts. When I come to a stop the gauge drops to 9. The lights dont dim, the jeep has no problems running or anything. I figure it might be the alternator, but am wondering could this be the voltage regulator?

 

At what RPM does it show charging? and what RPM does the jeep idle at...Tj

 

I will have to look at that. I know it idles smoothly with no hesitation or struggle. The voltage starts to go up as soon as i start to give it gas.

 

hey buddy i was wondering if you figured this out? i was doing a search and came across your thread. i have the same syptoms but all my lights, heater and radio light dim until i give it gas...my buddy thinks its alternator. JW if you had an outcome?

 

you can take it to most parts shops and they will throw a tester on there and tell you if your alternator is bad, for free, and if it is bad, problem solved replace it, if not, i dont know lol do what any sensable jeeper would do, start throwing random junk yard parts at it until it is fixed lol

 

thats the thing for an american living in the UK. we have to pay the exchange rate...even at junk yards. another wonderful plus is that they dont have a bad a$$ autozone or nothing like that over here to test an alternator. im damn sure i aint payin for a 200 dollar alternator if thats not the problem. lol. **** sucks but what can you do when uncle sam owns your life...lol

 

Got a hobby shop on base?

 

i use to have that problem with my eagle talon... the alternator couldnt handle the load... but i had led's inside,subs,and under glow...do you have anything extra that could be wieghing it down ?? lights ? i upgraded to a bigger alt and had no more problems...

 

yea. i we have a hobby shop. cant remember if they had a tester though. id imagine they would...didnt even think about it...lol...i dont have any mods to weigh it down. just stock. aftermarket CD player, thats it. use to have a sub and all that but took it out.

 

voltage regulator is supposed to keep the voltage faily constant, it's part of the alternator. if the lights arent dimming i would check the voltage at the battery when idleing if it's below 12, replace the alt.

 

Nope, not in an XJ. The regulator is in the pcm.

 

Try this. When your car is barely able to idle open up the fuse box and tap the "ASD" relay. Thats what caused an issue on mine. If that fixes the issue, it's a 15$ relay.

 

This same thing was happened to me at red lights. I would come to a stop, my engine would start running rough and my voltage would drop and sometimes it would die...I replaced the IAC sensor and it fixed the problem.

 

I had the same problem in my rodeo but never my jeep. The altenater wasn't putting out enough of a charge at idle. Went through 3 alternators in less than a year before I realized that pepboys parts suck. Hasn't happened since.

 

Wow, I didn't know that, Thanks!