freakaccident

92 Cherokee 4.0.

Recently the alternator hasn't been working as soon as I turn the car on. It's taken 5-10 minutes before it pops on and I see the voltage gauge go from 9-14 volts. Once it's on it stays on. Almost like something has to warm up before it kicks in.

Well this morning it didn't kick on at all on my way to work and now the battery is dead.

Any ideas?

Abovetimberline

It does not sound like a guage problem so I would suggest having the alternator checked to see if it could bee the problem,the other issue could be the pcm itself,the alt is controlled by the pcm which has an evr,electronic voltage regulator built in the only way to fix it is to replace the pcm. The last thing it could be is the battery temp monitor under the battery mounted to the tray,it monitors battery temp and reduces voltage if the battery gets to warm.
More than likley it would be the alternator.

gmsween

alternator is bad i would say. does it make any squeal noise what so ever?

freakaccident

I had it tested in the Jeep at the Autozone and their meter showed that the car was running on battery only and that the alt wasn't putting out any voltage. While we were standing there a little noise started. He said it sounded like the bearings might be starting to go bad.

Well I bought an alternator and had the battery charged. Hopefully I can get home on the battery.

My XJ has AC. What is the easiest way to swap out the alternator? Looks like its gonna be a pita.

gmsween

your going to have to take it out from the bottom of the jeep... it looks like it is going to be hard but it really doesnt take much. i think it only took me about a lil over an hour the 2nd time i did it.
1.) take belt off
2.) unbolt the front mounting bracket on the alternator. (aprx 5 bolts)
3.) undo the electrical to the alt.
4.) pull the bolts out of the alt. holding it in.
5.) unbolt the mounting bracket from the motor (aprx 3 bolts)
6.) pull it out, put the new one back in.

hope this helps

freakaccident

Ok thanks

ET JEEP

Make sure the pulley is correct. I purchased an alternator for a Dodge Ram. I put it on and then found the pulley was the wrong one. I had to remove it and go back and exchange pulleys.

I also had them test the new alternator before buying to make sure it worked.

I, too, was going to say work from the bottom. You could move the AC without disconnecting just for work room if needed. Good luck.

freakaccident

I read somewhere else that you can do it from the top if you remove the battery and battery tray. Which would be easier?

gmsween

you would think that you would be able to remove it that way, but i mean i have taken my jeep into pieces and from what i have tried i could never get it out from the top. it was really easy out of the bottom and you are not going to kill yourself that way. i think that is the easy way. but like everything that is just my opinion

Abovetimberline

The bottom is much easier than the top.

ET JEEP

Unfortunately, the Jeep is not here for me to take a look. Looking at a picture, it looks like it might work. The power distribution box may be in the way. Take a good look and see if you can reach the bolts. I have not done this replacement. I believe you have one long bolt with a nut on back. If so, you will need to get 2 wrenches in there. That is the way my Dodge alt. was held.

freakaccident

Looking at all of the bolts that would need to be removed from that bracket and the finagling to get it out the bottom I decided to try from the top. Was a piece of cake. Took about 45 minutes. Messing with the belt adjuster bolt was the biggest pita. Everything is working fine now.

I took the battery and battery tray out. Then pulled the top AC line over one of the battery tray studs. Then unhooked the wiring from the alternator and removed the two bolts holding the alt in. The alternator then came right out and the new one went right back in.

One thing I did find odd is that I don't have a battery temp sensor. There is a plug under the batter tray but nothing plugged into it. I'm guessing it failed at some point and was removed.