Last Friday our 2001 Deville died in the lot of vet (where we just put our fave pet to sleep, of all days). The car would not turn over and appeared dead to the world. The key was stuck in ignition, and I had no screwdriver to get it out. My bro in law came and attempted to jump, the car lit up all nice but the starter seemed to just tick. At the point I was able to get key out but no start. 15 minutes later a flatbed tow truck and a battery pack on the car, I gave it one last test, and VROOM she started up. Drove the car home and as soon as I shut it down, dead as a door nail.

Next day I found the battery post on the positive had broke right off, so I figured it shorted the battery out (is that possible?) Put a new battery in and the car was fine, for 5 days. Now its acting all goofy again, clock reset, key gets stuck, then it appears the security system kicks in or off and then the key comes out and the car can start. It does other flaky things, like dead at shut off and no power locks. When it is running I get steady 14.9 charge on the battery.

Other than Satan, and some codes I will get later tonight, WTF is going on?!

[QUOTE=jedimole]....

Next day I found the battery post on the positive had broke right off, so I figured it shorted the battery out (is that possible?) Put a new battery in and the car was fine, for 5 days. Now its acting all goofy again, clock reset, key gets stuck, then it appears the security system kicks in or off and then the key comes out and the car can start. It does other flaky things, like dead at shut off and no power locks. When it is running I get steady 14.9 charge on the battery....

QUOTE]

Not sure what you are calling a battery post on a side terminal battery. But I would inspect the cables that connect to your new battery for signs of corrosion and damage. If your original battery was 'broken', there was a very good chance of an acid leak, or an acid vapor leak that leads to corrosion that leads to intermittent electrical problems.

The positive screw to the battery was fine, but it look like the sulfur had burned the threaded/serated head off the battery. Bsaically I tugged on the red cap/cover and the whole thing came off from the battery

I will check the cables this weekend for corrosion, would this only occur on the positive cable or both?

I'd also look it over very good for corrosion.
Make sure the connection on the new battery is good and tight.

Acid leaks usually make this happen and yes it's usually the positive terminal.
I think I have heard of the negative being affected ONCE.

I had a similar problem with my Eldo about 2 months ago. The positive connector area broke right out of the battery case and was just floating there. It came loose finally one night and the car wouldn't start. A jump got her going again. Next morning, I jiggled the cable and it came off in my hand.

The replacement seems to be fine, but I did have a problem with corrosion around the positive cable causing very intermittent weird stuff just like you describe - the car would start up on a key-turn, then immediately die, and all the DIC info would reset - MPG, MPH, etc. This happened maybe once every 15 to 20 starts. The other day I pulled the cable off, cleaned it of all the corrosion, and sprayed liberally with white lithium grease (I didn't have any petroleum jelly..) and got a new plastic cover for it. So far, so good. Corrosion on the connections can be a real deal breaker.

I hate the side terminal connections. One of these days, I'm thinking of cutting off the cable ends, crimping on post terminals, and getting a top post battery. Any thougts as to why this would NOT be a good idea?