125K miles, car has ran perfectly since new. Drove it about 35 miles to a holiday party this past weekend, gave car to valet, he promptly kills it, of course. I see him start it back up and drive away. Go do the party thing, come back out, "we can't get your car started sir..." I go to look at it and on the way there the guy tells me they had to jump it 3 times. They were gone for 3 minutes, how is that possible? If they meant to get it to the parking space, it's not 500 yards from where I dropped the car off. Try the remote, nothing. Ok, battery is dead, let's jump it, I'll do it. Get it jumped, fires right up, take off the cables, turn on the lights, car dies. Ok, I guess the alternator is dead. I just happened to get it to the party with just enough juice left in the battery before it quit. Jump it again, let it sit for 5 mins to build some charge and have a guy follow me home. Car runs perfect, 75 mph down the freeway for 10 miles then the car dies. No warning, no nothing, just dead. Lights flashing on and off very rapidly for about 30 seconds, no power anything, just a dead car. Limp it off the side of the freeway and down the off ramp, get it towed home.

I take the battery in to the parts shop as it will need to be charged if not replaced and to buy an alternator. They test it, battery is fully charged. Hmmm, that's not good. I figure the alternator will go at some point anyway, so I'll just replace it as well. Put the new alternator in, button it all back up, reconnect the battery, horn works, lights work, windows work, turn the key, click, dead. Won't turn over, no more power to the lights, windows, remote, etc.

Sooooo, what now? Did these guys jump it because they didn't push the clutch in to start it and reverse polarity, frying my computer? Is there just a magic electrical short gremlin loose in the car? I am miffed because it was theoretically driven by someone for less than 500 yards, taking it from running perfectly to completely dead. I'm just not sure how that's possible.

Would REALLY appreciate any thoughts before I have this towed to a dealership so they can just dig through it while I pay them by the hour to stumble upon the problem. Thanks in advance!

 

Follow your positive and negative cables. The battery ground may be loose. The positive cable may be loose also where it goes into the fuse box or distribution box. There's either a bad connection, corrosion build up somewheres, or cable connection burned somewhere. It's a main power or grounding issue. If it runs at times at all, your computer is ok.

 

Update, bought a new battery tonight and threw it in, fired right up. Now I'm wondering if the new battery had enough juice to crank it up, but that I might still have problems with the PCM or something else. Considering that it died while it was running before, I can't imagine that it was the battery. So new alternator, new battery, still not convinced it's fixed. I will drive it around with someone following me tomorrow, more to come!

 

What happened was there was a cell that was dead in the battery. It will appear charged but it takes a special tester to tell if it has dead cells and even then sometimes it appears ok. Also fyi gel batteries cannot be accurately tested.

 

Yep.....bad battery and it may have caused the alternator to be over working. Sounds like you covered both issues and should have happy travels now.

 

Over time I had some batteries cause weird issues like yourself. Car starts to go to work, runs great, start it to go home and nothing. Sometimes a battery would still seem ok, but changing to a new battery solved my issues. I was told that with all the electronics in the cars today, just a small imperfection like a cell in the battery going bad can mess up driveability, gas mileage, etc?
As someone posted about the ground being an issue that happened to a friends Crown Vic that had bad corrosion from Winter driving and he had shut downs, dead car, fearing it was the computer. Cables were bad and the new ones solved the problem.
Hope you solved your problem.

 

if you take a lot of short trips your battery will die sooner, It won't be getting fully recharged.