civilzues

Went to Target with my Jeep working fine and then shopped.
Came back outside and started my Jeep and the "Check Gauges" light was on. THe battery was at '9 amps' and sat there the whole drive home. I then restarted my Jeep when I got home, light turns off and battery goes back to 14. Never did it run funny during the 10 minute drive home. So my questions is: sound like a fluke or do I need to have it looked at for this issue?
Could the cold affect this?
Thanks

Bustedback

Sounds like the alternator is on its way out.

civilzues

bummer. another trip to the repair shop.

tjwalker

I agree with Bustedback.

You could (and should) verify it with a multi-meter at the battery the next time it happens to be sure. Will take you 30 seconds. If the meter shows for example 9 amps and so does the dash gauge, the alternator isn't getting it done.

Bustedback

The gauge reads volts, not amps. If you're getting erratic volt readings it could mean the brushes in the alternator are worn and not making good contact 100% of the time.

civilzues

no erratic readings. Just this one instance where the the "check gauge" light was on.

salad

9 volts is not normal operating power for the battery, you would see 12V-ish if it was still running.

This sounds easily like a short on the alt. Happened to me in the past when it got wet. Check the wiring on the back. However I agree that internal problems could be the culprit too. These things aren't exactly mounted out of the way and take quite the beating.

Also take a look at doing a ground freshening. Cruiser54 has a great writeup that can easily be applied to non-Renix XJs

tjwalker

Oops....typed amps, meant volts. I've only replaced about a hundred alternators!!

A properly functioning charging system will show in the 13.5 to 14.0 volt range. I always verify with a hand held meter at the battery.

Freshening the grounds is NEVER a bad idea. If after freshening grounds, you don't have this issue again, I'd hold off on that new alternator. But if you see it again after grounds are verified, most likely the alternator itself.
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

civilzues

to replace the alternator I have a quote of $256.35 (part)+$65 for labor.
Seem reasonable?

Also getting this done at a shop i do trust and I'm moving to Minneapolis soon so I figured that I would just get it done here and not have to worry about it and I can't even change my own oil so..
Or should I ask them to "clean it" or ask them to do something else to it..?

Thanks everyone!

Reddskie

A new alt shouldnt too much i can get one on rock auto for 99-140$....dep on your year of xj id say under 200 for the alt .....if u can try to do it yourself its real easy and youll save the labor costs...plus u can have a beer when its done, and youll get to know a little more about the dang thing :-).........

couple things, first, i have the same problem except mine goes up and down whenever it feels like it but once down to 9v it stays there till shut off and turned back on...when turned back over it will show @11.5-14.4, sometimes it stays at 14, sometimes it kicks into 14, but always it will fail at some point.

i had my alt tested "they say" it passed, it is old and out of my 93' and into my 98'...my grounds are all clean, new terminals, clean connects on the back of alternator...just bought a new battery last night, started but ended up doing the same stuff...im thinking alt..also (dont try this at home lol) disconnected the terminals after starting vehicle...jeep shut right off...alt...sometimes turning the key after sitting wont start at all...(nss? dif issue?).....

hope i could help...and could yal help? lol before my brandy new battery dies :-) mucho gracias

civilzues

well, I have another question-I've only seen this once. Should I even be concerned? Shouldn't this be happening more and more frequent?
either way, I am getting it tested 12/8.

Reddskie

Mine started happening about 4 weeks ago....happened one day then not again for a while.....then more and more frequent.....awesome way to test alt is to test your battery with a multimeter with xj off......then test top terminal of alt and ground if they read the same thats a good start...then do it with the xj running....careful if u have no shroud for the clutch fan like me lol....there is a great right up for this by rrick (yes 2 r's) ....its under some kids post " wont start need help" found it by typing "alternator" in search.....3rd or 4th page.....hope that helps......i just replaced.my alt from his writeup and so far it fixed my problem, my battery on was reading 13.8...off....12.3.....alt now after install ...both tests read 14.2...short if this doesn't make since but I've ben up since 330 am and its 10pm now lol job only took me an hour cuz I was cleaning grounds as I went

tjwalker

Freshen your electrical grounds as I outlined in post #8.

If it doesn't happen again, don't worry about it. If it happens after freshening grounds, then the alternator should be addressed.

civilzues

two test. One at 14.38 and one at 14.35. I think it was just a glitch

but after two test and who I had test it-I feel safe (for the time being).

Thanks everyone for the information-can't tell you how much I appreciate everyone on here and the information they give me

RTorrez1

Yeah, You never want to do this! You run the risk of frying the computer. It was fine in the older vehicles without a computer but not with one. If you want to try it do it at your own risk!