Complete power loss throughout Jeep after alternator and wiring upgrade

Hey guys, let me me start by saying I'm a new member to the forum but am not new to using this forum. I've used many of your guys' threads when researching upgrades, reviews, etc and they have all been plenty helpful. Today I am here not for research but I have ran across my own problem that has me beating my head against the wall.

One week ago my alternator failed when coming out of the store and I had to limp it home on the battery. I ordered a 96 zj 136a alternator and a mixture of 4awg and 2awg cables to replace the factory grounds and alternator to pdc wiring as I am running various lights and my winch. The previous owner had things hardwired and rigged horribly so I figured it was time to settle it and dig deep.

I clearances my brackets and the block/timing cover,mounted the alternator, replaced each ground 1 by 1 as to not mistakingly mix anything up. This is just my usual procedure of doing anything electrical related, always 1 at a time. I started by replacing the grounds, then replaced my alternator b+ to pdc post with a 4awg cable running an inline 150a ANL fuseholder. After buttoning up things, I turned the key and had absolutely no power to anything. This includes gauges, radio, ignition, etc. My lights that were hard wired to the battery will not even turn on.

Since this has happened, I have checked the battery, checked and cleaned all grounding points, checked all cables for being loose, checked all fuses, tried jumping it, tried 2 other new batteries, I even tried putting my oem alternator b+ to pdc cable back in....nothing.

Has anyone heard or seen of this before? I am completely lost at the moment. I do have a very good multimeter but have never known how to check relays, etc with it before. Only simple things like continuity, ohms, and voltage on small systems like a battery or a single wire. Any help is appreciated and thanks in advance.

Did you replace the battery positive to PDC cable? This cable go to the PDC right connector which is on the appositive end of the alternator cable.

Standing at the front of the XJ, of the two cables (in your case 4 AWG cables) on the PDC, the left cable connects to/from the alternator and the right cable to battery positive which also parallels to the starter motor.

HTH.

Yes I did replace the battery POS. to right side pdc post cable as well but the previous owner had them together on the same single post, right hand side. Would it benefit to make a post on the left and bridge them with the anl fuse like your describing? I've seen that setup before in pictures. I'd like to retain the waterproof case if possible but honestly if that fixes my current issue I can reevaluate the waterproofing later on.

My current set-up is alt b+ --> anl fuse --> right side pdc post --> battery positive. The left hand side post is not there but the plastic shroud/keeper is there. I'll run out there and see if I can find a bolt, shave the head a little, and make my own left hand side post to create the bridge you speak of. Then I'll readjust the cables to match what your saying and see if I can get power.

When things act weird I go back to basics. Have you checked all your new cables for continuity? It is possible to get a new cable that just doesn't conduct, poor crimp or bad conductors in cable, rare but possible. When I was rebuilding my 1952 Ford 8N tractor years ago I had problems with poor charging that came down to a bad cable, even though the cable was new. I make my own cables now and do check for continuity and resistance when I build them. Also possible is the alternator, while new, is bad.

Use a voltmeter and follow the voltage, point to point! Seems like a dumb question, but is the fuse good?

Ok, so I bridged them with the anl fuse after making a new left side post, still not a drop of power to anything. I have checked continuity on a few of them but I am currently going through the rest of them. I had bought these cables a few days ago from an online distributor that makes cables to your specifics, they look and feel well put together but I do see what your saying and it is possible they are bad. Underneath the insulation could be bad and I'd likely never know. If the alternator was bad, is it possible that it would cause there to be no flickering or anything when the key is bumped? I mean I literally get nothing, no chime, no gauge flicker, no radio flicker, she's just completely dark and dead. Id like to do my own cable but from what I was reading it sounds like you need a hydraulic crimper to do this large of wire, I'm currently limited to manual/hand crimping.

Yes the fuses are good, not a dumb question... I questioned it myself. Going through the ropes with the voltmeter now, thanks guys I appreciate your suggestions, I was running out of my own for sure.

There is continuity in each wire and fuse that I've touched since it was last running and driving :/.... I forgot to mention that I had replaced the battery positive to starter as well but that one also checked out fine for continuity and connection.

You sure you didn't fry your battery? -- Check it with a load -- try to hardwire something to it, and aux light, a horn, anything you can just to draw power

Just because your voltmeter shows 12 volts doesn't mean your battery can give you amps to do the work

Gotta confirm good battery -- even pull the battery and try it in another vehicle if you must

Hmm :/, no I'm not 100% sure but I tried a second battery of mine and even hooked my wife's van up to it. I'll have it load tested today to make sure though, it's definitely it'll worth the shot. Thank you.

I did go grab some crc electrical cleaner because the previous owner went mudding with the doors off a few times and never attempted to clean the interior fuse box that had been caked in mud. The fuses we're fine in that box, and the pdc box, but I'm wondering now if maybe my tampering of the ground system brought up some old issues that he tried to get around by hardwiring things to the battery. I'm just trying to wrap my head around why no system in the car is getting power (based on turning key and trying all switches, not a true volt test).

Today's goal is to load test battery, test alternator, clean fuse box and all connections that I've touched using the crc cleaner, and anything else I can think of.

Battery checked out fine and alternator checked out fine. This may be a stupid question but should I have cont between the neg and positive terminals at all times? All times meaning with key off and battery connected as well as key off and battery disconnected. Keep in mind I'm not very electrically savvy, thus why I created this thread.

You should have power, even with no alternator. First, turn on the key and measure voltage between Battery - and the firewall ground. If there is more than .3v or so, you have a bad ground. After that, measure the voltage from the ground to the Battery +. You should have 12v+. If that is fine, measure from the battery to the input terminal for your fuse box.

Also measure from the battery+ to the positive (big) terminal on the starter. Again it should have no voltage.

.... So battery negative to firewall ground shows 12.54v...... I think your onto something here. I'm going to keep digging... Ground to battery positive shows -0.00 on voltmeter.

If there is a complete loss of 12 volts in the XJ then it should not be too difficult to trouble shoot. However, most of us overlook the simplest solution and go directly to the more difficult areas.

Be certain the battery is good (you verified that already) and battery connectors are clean and tight.

As someone else mentioned, check and recheck all the cables you replaced that they are capable of carrying the power needed. Simply OHM testing may not be enough. Try pulling on the ends of the cables especially those between the battery and ground both the engine and the body.

Do the same thing for the positive between the battery and the PDS. Yes, on the 1996 XJ, the battery positive is connected to the right side of the PDS, i.e. when standing in front of the XJ it is the terminal closest to the engine.

There is a 60 AMP fuse in the PDS, I think it is fuse #8. check both sides of that fuse for 12 volts. If 12 volts is on one side and not the other, then the fuse is bad. The fuses could be tested without removing them. If there is no voltage on either end of the fuse then go back to the beginning of this post and verify every cable and connector.

When probing for 12 volts, I usually connect on test lead to the battery negative and the other lead on the unit I am testing.

Novacane327 said:

.... So battery negative to firewall ground shows 12.54v...... I think your onto something here. I'm going to keep digging... Ground to battery positive shows -0.00 on voltmeter.

Click to expand...

This says you have an open ground from the battery to everywhere. The main ground connects to the bolt that holds on the dipstick.

You can verify the bad ground by simply hooking up a jumper cable. Use only the black lead. Connect one end to the battery - and the other to the engine block or firewall. If it starts and runs, you have proven the hypothesis.

Yup power to both sides of the 60a fuse in pdc. 12.54 to both sides of it. I'm double checking every ground on this thing now,

Old man, I'm going to check that now. Thank you!

Wow, old man you were right. She started right up as soon as I did that. So I need to find a bad ground or does this mean I should connect the ground-loop by adding a ground between firewall and battery?


Edit: I don't mean to sound so suprised that you were right, it's just been a long week of chasing my tail and I can't believe it's finally coming to an end.

Novacane327 said:

.... So battery negative to firewall ground shows 12.54v...... I think your onto something here. I'm going to keep digging... Ground to battery positive shows -0.00 on voltmeter.

Click to expand...

That would indicate you have the battery reversed!