Over the weekend I was at the drive thru grabbing a late dinner with the defrosters on heat and high. While sitting idle I noticed that the voltage on the battery was quite a bit lower than normal. Once I got through the line and moving eventually the voltage went back to the normal range that I am used to seeing. I have not noticed this kind of behavior before but I am wondering if this might be a prediction that the alternator may be getting ready to fail me. I have had the XJ for a year and it has a new battery but I cannot say that the alternator has ever been replaced. Thanks in advance.

 

Advance auto can test it for free. Not really an answer to your question I know. The more stuff you turn on the more amps get drawn out. Only seen 14v on my dash once

 

Yes, it very well may be.

If so, congratulations on being observant and thoughtful, instead of being clueless like most drivers and waiting until it just breaks down and leaves you stranded.

Getting it checked at Autozone is a great first step. Don't assume their word is the final word, but a free test is hard to turn down.

 

How are your battery ground connections at teh block and wherever else they go?

I'm more used to the earlier models but it's sure worth it to refresh them. where does the blower motor ground?

 

I am going to have to look into the grounds, I replaced the end at the battery and the others that are in plain sight seem to be okay as far as the blower motor I am not sure. I also don't know why I didn't think of autozone to test it, I took the starter there at one point. I have a little time and a few bucks into the car as it sits and I want to keep it for as long as I can so I will most likely try both next week while I am off for the Thanksgiving holiday. Thanks for the responses.

 

Cliffy,let me know if it's your alt.
I found great sources for our year.

 

Hey buddy lots of times when the ends get bad like rotten and you replace them it can mean more issues inside them as well down a ways. When I have a cable that needs a terminal on it I "Always" replace the complete cable with a new one either home made ("IF" you have the proper tools) or OEM.


As always grounds can be an issue.

 

Check voltage at the terminal on the wire, then on the posts directly

The internal gauge is really susceptible to loads. Blower motor is on the internal power circuit and is enough to make the gauge drop inaccurate

 

Will do, I intend to dig in on this next week. Thanks.

 

Thanks for the advice, I only replaced the end because the other one looked rough and it may have been a safety inspection issue. I agree with the cable replacement idea and intend to do it on both my XJ and daily driver as well as refreshing the grounds I didn't realize the importance of the ground until I bought a twenty year old XJ. It is on my list that I made from Cruiser's list but it seems like things keep popping up preventing me from getting to it.

 

On the wire of the gauge- 1st and then the battery posts ? Thanks for the help.

 

check voltage on the battery posts and the battery wires, to see if there is a similar drop as what the gauge shows. It is probably much less, if any.

 

Fwiw the only time I saw 14v, even, on the dash, was when I just cleaned the post terminals and clamps then sprayed them with that anti-corrosion stuff. Just after starting and before turning anything else on.

 

Thanks to all for the feedback, I haven't had a chance to dig into it yet and probably won't until Monday but I will get back with the final fix. @Crab, what had me concerned was that the gauge was sitting at about 14v like normal and dropped down towards 9v just outside of the red segment on the display.

 

Verify that all connections on the alternator/generator are free from corrosion and are secure (see pic).


Verify the ground connection (G103) at the coil mount bracket is free from corrosion and is secure (see pic). Pic says 97-98 but is the same for a 95.