Weeks ago I was driving home and the "check gauges" light came on and the alternator gauge read no power. Going through the usual avenues, I replaced the alternator. Didn't stop. Then the battery. Didn't stop. I cleaned all the connections and followed the wires as best I could only to not find the smoking gun. I brought it to a shop that specializes in electrical and paid them to tell me what I already knew "yeah, it's not charging, might be the computer". I ordered a new ECM pre programmed and installed it. STILL NOT CHARGING THE BATTERY. Prior to replacing the ECM its been giving me problems starting and only turning over after spraying some carb cleaner in the throttle body, its still being tough and just something worth mentioning in the post.

If anyone has suggestions I'd really appreciate it, the auto shop I would eventually have to bring it to will charge 600 just to start going through it. I'm not in the place to afford it at the moment so I've gotta figure something out! Thank you!

 

A shop that specializes in electrical would not say something like that. A charging problem on a XJ is a bread and butter job for someone that does a lot of electrical. It would be easier on the XJ then on most new vehicles.

Do you know how to test for voltage and voltage-drop using a multimeter? Are you willing to watch some youtube to find out? Low charging voltage usually exists somewhere between the alternator and the battery. (there isn't a whole lot between those two components) so on the XJ, it usually comes down to a bad alternator, a bad ground to the engine block or battery-to-chassis, or bad cables. Jumper cables can be used in conjunction with a multimeter to rule out bad existing cables.

I helped a guy on here (for a long time) with the the same problem. It started as a failed alternator, followed by a bad alternator (out of the box). Which really put us off track, because we were all quick to assume that the replacement alternator could not be the source of the problem.

 

Which ones specifically?