89 Cherokee - Is my alternator bad?
 

Hey guys - newbie to the forum here!

Just got my first Cherokee. I've had a couple wranglers (and still do) but decided to get a practical daily driver. The thing is in good shape. It's an 1989 with the Renix 4.0.

Since last night I've noticed that the voltmeter keeps dropping. Last night it was at 12, then it started dropping more. Today I had a little trouble starting it. I went to go to emissions and sat there waiting in line and I saw it start dropping more. The radio kept turning on and off, the A/C blower motor stopped blowing as hard. If I opened my door I'd see the RPMS drop a little since the dome lights kicked on. Towards the end I couldn't really get it to move forward and it finally sputtered and died. When I tried to start it it just clicked and clicked since the battery was toast.

I'm 99% sure this is a bad alternator since I'm thinking it's been running on the battery the whole time. I know the PO literally just put a new battery a day before I bought it and I know the A/C blew harder last night than it did this morning. I also heard the classic alternator grinding/shaking towards the end when trying to move it.

Does this sound like I've got it figured out? Or is there something else I need to look for on this thing? Just asking since I know the Renix 4.0's are a little funky.

Well if i remember correctly, our renix will never show an actual correct reading unless you add some grounding wires. (Like at the blower motor, etc...)

you might want to get your alternator tested, i think they do it at any auto parts place. I bought a little device from harbor freight that has 3 lights and it will say if your battery and alternator is charging bad, neutral, or good. You could also use a multi meter and see what voltage is returning to the battery. I think your looking for anything above 12 volts, anything below your alternator is crapping out.

Thanks for the response! I know these motors are a little bit funky. Unfortunately it's sitting in the emissions parking lot and I don't have access to much, I'll probably grab my voltmeter and a 13mm ratcheting wrench (brought my toolset but would like to have to loosen the belt) and let you know what I find. I'll give her a jump and see what is getting to the battery.

On a side note, the owner advised me he has never replaced the alternator in the 16 years of ownership, so I'm feeling pretty confident that's what it is.

Translation; This jeep has a bad alternator. But this new battery should get you home.

Lol, i think you got it pretty well figured out. Jump it, then put the meter on it. On a thoroughly drained battery, you should see 13.5-14.5 at the posts once its started. 12 or lower? Bingo boingo, bad alternator.

Haha! The PO was an older gentleman and the car was at a secondary home and wasn't used much. He did some great work to it but when he got here from CA it didn't start and the battery was toast so he grabbed a new one.

Either way leaving at 5 I was able to get the new alternator, replace it in the emissions parking lot, go through emissions, and still made it to dinner by 6:30. It honestly took longer getting the tension off the belt than the actual alternator removal. I also had a skid plate on mine that I haven't seen on many XJ's. Did they come factory with a skidplate?

With the new alternator the Jeep runs like a top! Thanks to everyone for their inputs!

The front skidplate is a factory option, but one i havent seen often. Ive had a good handful of XJs, the only one that had one was a RHD Limited imported from Japan.

Glad shes back on the road man!
:thumbup1:

Yeah it caught me off guard for sure! I've never seen one on an XJ before. Thank you I'm glad she is too!

Is there a place for build threads or anything like that on this forum? I want to start documenting the preservation of this baby! This is going to be a daily driver, I've already got a built Wrangler :grin:

Sure is. "Jeep Builds" > https://www.cherokeeforum.com/f46/

:thumbsup: way to go man... yeah, mine has a front skid but i got it off a friend that pulled it off another jeep at a junkyard.