ol_blue

First off, let me apologize for making my first post a need-help thread. but this is where I currently am in life:

04 WJ, I6, roughly 150k miles

Friend borrowed the car and decided she was going to jump somebody off. Cables were correctly hooked up to my battery, but the open leads were apparently touched together multiple times and maybe even put on to the dead battery backwards (she isn't really sure). After this, the car continued running until it was shutoff, and now it will not start. or crank.

What I've done: had the battery replaced, old one tested bad. Did not help.
Pulled the alternator, it tested good. reinstalled
Pulled the starter, also tested good and reinstalled. (even tapped on it while trying to start vehicle) Nothing.

The most you can hear when the ignition is turned is a slight clicking noise coming from the starter. Every once in a while it will make a very weak attempt at turning the flywheel, almost as if the battery is dead. But its fully charged.

My question is, can anyone point me in the right direction for further electrical testing? is there any sort of main fuse I should check? My fear is that the PCM is done for. It literally acts as if the battery is completely dead.

Again, sorry for this being my first post. But I'm kind of dead in the water and have very little options other than having it towed. So any help is greatly appreciated.

Ol_blue

Kingfisher

Clean terminals, and grounds.
A little sandpaper or emery cloth to shine 'em up!

ol_blue

Forgot to mention that, terminals have been replaced. Didn't help, but needed to be done anyway.

GI-Jeepin'

It could be the PCM, but before you write that off have you checked the starter relay? are any other systems working when you turn the ignition on? Wipers, Lights, Radio, Horn?

Red River T

If every once in a while the starter makes a weak attempt at turning the engine, that makes me think it is not the PCM or a fried relay. Seems those would result in no power at all to the starter.

My prime suspicion is a connection, if not the battery terminals, then maybe one of the engine grounds or the body ground. I don't know about "modern" vehicles, but I know on older ones you can connect straight to the starter terminals with jumper cables to test your starter/battery. They make cables with a switch on them for doing this. Mechanics who work alone have these so they can crank the engine from the engine compartment.

The replacement terminals, if they are the clamp-type, did you wire brush them inside where the cables make contact? Yes, I know, even new ones. I've read numerous posts from guys who sure sound like they know what they're talking about say that Jeep electrical systems are touchy and that you need clean, shiny surfaces when you make connections.

Kingfisher

^^^ What he said!.........

dave1123

First of all, a fried PCM won't make it not crank. Put a voltmeter on the battery wire where it enters the PDC (power distribution center, that box with all the fuses and relays in it under the hood). Watch the voltage when you try to crank it. If it stays up, you've got a bad connection (open) in the starter solenoid wiring. That wire to the starter should be getting hot if it's shorted. If it drops way down, you've got a bad connection at the battery.

Check the starter relay by putting 12 volts to the small wire at the starter. If it cranks, the solenoid is good. IDK about jeeps, but some vehicles have fusible links in the heavy supply wiring. They are fusible sections built into the wire and can't be fixed if they blow, they must be replaced. Check the smaller red wire that goes from the battery clamp to the PDC.