All seems to be OK, considering your 7 year old battery is acting as a seven year old battery.
What was the battery condition at the most recent service ?
I think the engine should NOT turn over until the seat is in position..But this is most trivial....

What is not trivial is the dealer trying to charge $100 for an estimate..This makes no sense.

Yeah, $100 for an estimate! Doesn't that suck. I hate going there.

I ended up doing some diagnostic code self checking. A friend of mine told me to do the key thing where you turn it on and off a few times and then a code displays in the odometer which could indicate what's wrong. So I did that and it said something about low voltage. So instead of spending $100 on an estimate, I took it to Sears and got a new battery for $65 and it's running fine now.

They would not charge $100 for an estimate, but they may well charge that for diagnostics, in order to provide the estimate. The days of simply taking a complaint, and knowing whats wrong with the car are long gone. Even similar sets of symptoms can have multiple sets of causes, so every problem must be tested as a unique occurance. Otherwise the result is failed repairs and the customer having to bring the car back again, and again.

Now when I see a line like this "I hate going to the dealership because they gouge me and charge $100 just for an estimate." combined with the fact that I'm not 100% sure what a 300M is, (BMW, Mercedes etc?) I see a customer that really does not understand what it takes for the techs to be there to provide the service for their car. For me to tool up and support those cars fully, I would have to spend, some $40,000 and there is no guarantee that one would ever come in the door let alone enough of them to make buying the tools and software a reasonable expense. The dealer HAS to have this equipment and it changes with each year. I have equipment that will allow me to do some services on these vehicles, but not everything. Auto repair is expensive, and repairs for the higher end cars moreso than Fords and Chevy's.

"So I did that and it said something about low voltage. So instead of spending $100 on an estimate, I took it to Sears and got a new battery for"

We will leave it at this. Could a battery be the problem? Sure. Is just a bad battery the only possibility, NO.
In the event it is more than just a battery, and if a shop had done what you did, they would be rippoffs, right?

All I know is that when I take it to the dealer, it's a major pain in the butt, it takes forever, and it's always much more expensive than anywhere else.

And for your information, a 300M is a Chrysler product and it was the 1999 Motor Trend Car of The Year. It's a very popular car, I'm surprised you've never heard of it as it's the predecessor to the Chrysler 300C which is the 2005 Motor Trend Car of The Year.

As for the estimate, yes I understand that there are diagnostic tests that need to be performed on every car and for certain, high-end cars those tests can be more difficult to do on other types of cars and parts are more expensive as well. I do know that on my 300M it is difficult to change the oil and difficult to change the battery is located down in the right fender and you have to actually remove the tire and that only one terminal is exposed so you have to remove some plastic housing, hoses and other parts to get to the other terminal which needs to be disconnected first.

I am not just some dumb chick who wants her car fixed in an hour for $20 while I stand there with my poodle in my purse and supervise. This is the same dealer who broke a perfectly good part off of my car while they were changing my oil and tried to charge me $350 for the replacement parts and labor when it was their fault it broke off. This is the same dealer who charged us $100 last week to look at the coolant in my Jeep and determine in under 5 minutes that I needed a new radiator and thermostat for $900. Fred's Auto down the street ran better diagnostics, more quickly, came up with the same diagnosis and had the work done in under 2 hours for $450 and offered to get me lunch or drive me home while they worked on it then pick me back up at home when they were finished.

And yes, I do realize that it could be more than just a battery issue but I'll take my chances. The problem has gone away, I probably needed a new battery after 6 years, and the diagnostic code is no longer displaying. And also FYI, my beef is with the dealer not shops in general. I find that I get much better service and prices by NOT going to the dealer. If you work for a dealer (it didn't sound like it or you're a Ford/Chevy man) I apologize if I offended you, but the Chrysler dealer where I live bites pure and simple.

"In the event it is more than just a battery, and if a shop had done what you did, they would be ripoffs, right?"
I actually had an appointment for an estimate/diagnostics (free by the way) for today until a friend on another message board told me about the code checking and that he had the same issue on his Sebring (another Chrysler product in case you've never heard of it), got the same code, changed the battery and the problem was corrected.

Thanks so much for your very helpful advice, John. I don't know what I would have done without it.

Hopefully you will be spared the hard lesson some people are going to get to learn. When the Sears of the world get the gravy repairs, instead of the shops that have truly invested in diagnosing and repairing your car, it does hurt the real shops ability to stay in business. The Chrysler dealer sucks, they need to fix that, when you get the chance to tell them they stink, do it and be complete about why. Freds was great to you with your Jeep. Thats Great!! Too bad though you managed to forget just how good Freds was when you bought your new battery from Sears. Guess Freds wasn't good enough to get all of your business. Thanks for confirming that the attitude I thought I picked up on. I hope Freds survives and is profitable so the next time you need them they are in business, and you won't have only Sears and the dealer to choose from if you need diagnostics performed. Oh yea, Sears doesn't do diagnostics, so if you lose Fred, you'll only have the dealer that stinks to go to.....

It might be just the battery.But more then likley its the first sighns of a Chysler and there long reputation of having electrical problems such as shorts and unexplained electrical problems beginning to show its ugly head.

Thats why you see so many Mopars on used car lots cheap and why when you go to trade on in there not worth much.Example Chrysler Lebarons that were only a few years old many convertibles a few years ago these could be had for prices like $4000.00 for a nice looking low mileage car.They sold like hot cakes.Same thing several years earlier with the K cars.Also the Chrysler NewYorkers were dirts cheap and not priced like a Mercury or Chevrolet or Olds or Buick or Ford or Lincoln in its same class.But when you cashed in on the savings you found out why.Cars that were fairly new but would do strange things like Just die along the road power equipment that drained the batteries over night.

When I think of Dodge Chrysler Plymouth Mopar I think of shorts.If you think im just full of BS ask around and take a look at used car prices and notice a used one can be had for less then the others.Then ask you self why.

I am with John G on this matter.

For too long mechanics have given free diagnostics, free service(fill her up, check the water and oil and air); thus spoiling the people.

Now automobiles have become so complex and so expensive to diagnosis and repair that only the big shops and big dealers can survive...

A far as a "300M" being a "car of the year" goes - this means nothing.The Chevrolet Vega was once a "car of the year" !!
And if the 300M is a Chrysler, say that it is a Chrysler, this is not difficult, is it ????

Motor Trend ,and the other rags, exist only to sell cars and accessories, not to impart any useful info to the buying public.

One should read Automotive Engineering or the magazine found in the better shops( I cannot think of the name of it, but it is good and expensive)...Good, useful knowledge, as with all else, does have its price..

What is the amperage for the 300m batteryes ( year 2003 ) ?
I want to replace mine and i dont know what to buy !
10x

Cumnatu. Any good shop that sells batteries will have the
replacement list of the battery for your car. Even WalMart.