Ok so here's my very serious dillema...just today I went to get into my jeep to go out and run some errands. When I turned the key to the starting position the starter clicked once and then all of my power all the way through my jeep was cut automatically. So I know that the PDC on these things are known for problems with a certain wire...the green one to be exact on the front side that takes power from the battery. I grabbed the wire and wiggled it slightly for alittle while and I got power back...I went to try the jeep agian and same thing. This happened three more times. I cleaned up the contacts and nothing....it looks like theres a larger amount of wire between the power wire and the connector to the PDC, so I assume this is a Fusible link? I went all over trying to find something...no luck. Not even at a stealership...Does anyone happen to have any idea whats going on with my jeep? Is it the PDC its self or just the wire or fusible link??? I can't find anything anywhere on it and I would really apperciate any help I could get, I need my jeep for my new job, So I need this fixed as soon as possible...Thanks in advance

 

That green wire is a fusible link between the PDC and the Alternator. It's just a chunk of #10 wire, it will open somewhere north of 100 amps like a fuse.
The red wire is the PDC/Battery connection.

What do your battery cables and connectors look like? Are the cables corroding from the inside out? Battery fully charged?

 

98:

 

Battery is completely charged and was new when I bought the jeep, I just replaced the alternator just two weeks ago. I'll go out and take a picture for you to show you what they look like, its just a green wire with shrink wrap running to a black wire with a white tracer on top of the red power cable from the battery.

 

Here's the picture: And Also do you happen to know of any other way that I might be able to fix this? I was looking to buy a fuseable link from an autoparts store and from the stealership but no one had anything.

 

You really don't buy fusible links per-se, they're just a short piece of smaller gauge wire enclosed inside a non-flammable wrapper.
The drawing says this one is made of #10 wire. The rest of the cable is larger (#6), so the #10 opens up first.
So.. grab about 4" of #10 wire. Cover it with non-flammable heat shrink. Crimp a connector on one end to mate with the PDC. Attach the other end to the existing black/white alternator cable using a step-down butt connector, or ferrule and solder.
(not the kind of butt connector you crimp with a hand tool..these are heavy-gauge to carry high current and require a crimp fixture and hammer. Like battery cable ends. If that' isn't whats there now...someone already messed with it.)


But...are you sure that's the problem? That green wire is the alternator feed. The jeep should start without it, just won't charge the battery. I'm curious about the condition of the red battery wire underneath, the connectors at both ends, and perhaps the power stud they are both tied to at the PDC. Is it firmly connected to the PDC power rails?

 

I'm butting in here...I didn't even really read the thread! Your thread title as a nearly perfect description of a crust on the battery terminals and the clamps.

Works some til you hit it. Gota' have shiny lead on all four surfaces there. Shiny! Lol. I'm sure you are in good hands....

 

The red battery cable seemed to be in good condition but I didnt follow the wire all the way down because of the massive loom of wire that is for the charging system. Its secure on the mount and I cleaned all the connections just for fun...Nothing. I might be able to inspect it agian tomorrow after work but I have no clue right now, I'm trying to help solve this the best I can

 

Maybe if you had a $5 meter, and even someone to turn the key it might help to isolate it. Too often people don't get that lead actually shiny. I use a small blade to break that crust. Just grey and clean looking doesn't always get it.

 

I actually have a very exspensive snap on meter...I just dont have the time to use it, Going to class and working now dosent help with my time frame. Are you talking about for the PDC terminals? I sanded them down to bare metal and then put them back on

 

Well...when it won't power up, grab the meter and start tracing. Battery first, then the main power connectors @ the PDC and at the starter solenoid. From there check the input to the ignition switch..then the "start" and "run" outputs with the key on. At some point you'll find where the voltage is dropping out.

Also check for any significant voltage drop in the grounds. In fact I might consider doing this first.
2VDC or so meter scale. Neg. meter lead on battery (-), pos. lead to engine block, chassis, starter case, etc.
Try each location while you load the battery with the headlights on, blower running, etc. Crank the starter motor too if you can. The more current you can run through the grounds the better- makes the voltage drop larger & easier to spot if there is a problem.
Should be a few milivolts voltage drop at most, even with a heavy load. More and you have a high resistance ground connection somewhere.

It doesn't take much resistance to really screw up a 12 volt system.
On 80 amp starter, merely 0.1 ohms resistance can drop 8 volts, leaving just 4 at the starter...which of course won't turn.

 

No, I'm still going on about the battery terminals & posts. Please excuse me, it's just that this "medium" can be tough. Too often guys think they got them right, (they "look OK"), but they didn't actually scrape through that hard crust. I don't mean to insult your intelligence! Just not being able to actually touch it makes it hard from here. That's it, I'll stop..I promise! (shiny lead though, shiny!)

Great info as usual Radi, and thanks. I need to get more familiar with that voltage differential test myself. Clever.

 

Heh. And no lumpy crunchiness where the cable attaches to the battery terminal. Battery acid gets in there and rots the wire, which you can't see because of the insulation covering it. But you can sometimes feel the lumpiness, or hear it crunch when flexed.
Can't tell much from an ohmmeter test..the minuscule current for the meter passes just fine.. But 80 amps for the starter won't. Have to measure the voltage drop across the cable with a load running through it.

 

I had the same proble a while back where i would wiggle the wires on the positive terminal and power would click back on. I disconnected all the wires cleaned them put some di-electric grease on the ends of the wires and hooked it all back up and has worked ever since. I'm not sure if that id you exact problem but thats what worked for me.

 

I have to say your persistance in shiney leads has helped alot more then you know lol That pretty much did the trick. She's running now agian!

I checked the PDC, Starter and then the interior 12V outlet for power before I got the power to cut on me agian. All had power before I had a friend of mine attempt to start it then just like that jeep wide, not just under the hood the power was cut completely. No power anywhere except the battery (which also checked out to be good as well) So just by a random circumstance my buddy happened to have wiggled the ground cable running to my fender well...well thats all It took apparently and she started right up! I did a bunch of tracing, testing and measuring of my starting/charging circuit wires and it turned out to be a crappy body ground. The only reason it didnt ground there was because there was a good amount of bondo blocking steel for a ground. After shaving it down and doing a bunch of cleaning sanding and then battery protectant blasting She runs just fine agian...thank god.

I did the same thing minus the dielectric grease, I just used battery post cleaner/protecant and called it a day...and what a day. An hour and a half of testing for a stupid body ground...