hey guys my 98 jeep cherokee keeps losing power. it will start up at about 12 volts and run ok (kind of rough) but as soon as i put on the headlights and/or radio the voltage drops down to 0. If i disconnect the battery while the car is running it cuts power immediately. Does this mean it is the alternator? Also 2 of the 4 bolts on the bottom of the alternator that connect the black peice with the green wire are broken off. could this be the problem? Thanks in advance.

 

First of all...NEVER DISCONNECT THE BATTERY CABLES ON AN XJ WHEN IT IS RUNNING!!!!!!! As soon as you said what the volt gauge was doing with the Jeep running and when you turned accessories on, I knew your alternator was bad. You're lucky if your ignition or ECU is not fried after pulling the battery cables with the motor running. You can take your alternator and battery to you local parts store and have them both tested for free. Check your battery and alternator wiring for cleanlkiness and security. Get your battery charged and replace your alternator and your Jeep will be fine again.

 

X2
Do not remove the battery on a newer running vehicle. This can cause voltage spikes that can fry expensive parts very quickly.

 

Just went through the same issue. New Alt and belt she is good to go.

A freebie is check and make sure the belt is not slipping.

 

thanks guys

 

before i buy an alternator, is that the only thing that could be the problem? theres a brand new battery in there. could it be something with the wiring?


and also what is the easiest way to remove/install the alternator.? through the bottom or take out the battery tray?

 

Yes, you should inspect the battery cables at both ends and the alternator wiring and connectors. Bad wiring or connections can definitely cause this problem, too. That is why I said to do that in my message above.

 

If you disconnect the positive terminal while the car is running, and the car continues to run then the alternator is good. If the car cuts off then the alternator is bad.

 

Sure if you want to replace the ECM and many more electronic components. You will fry something.

 

Your best bet would be to change the alternator. Similar problems when mine went and it took about an hour and a half to do...that time includes those hard to get off bolts, the occasional break, etc. It's not a bad job. When you get it unbolted it takes a little experimentation to get it out but if you jack up the engine a little it should slide out pretty easy. I got mine rebuilt for $80 and it works great.