There is nothing to fear when replacing or disconnecting a battery on a Chrysler product. I have replaced hundreds of dead batteries and disconnected batteries daily while repairing vehicles with no consequences with the exception of a few early '90s radios that locked up.
There are know issues with the WCM/SCREEM modules (immobilizer) on these cars but the the symptoms include no engine cranking and loss of RKE function.
Tester, etc: I have a 2006 Chrysler vehicle, and I assume (yes I know what that word can get you) that it uses the same system, as the same keys can be used on a range of vehicles including my year and a 2007. If you put in a key that has not been programmed, the car will still crank and start–it will just die within 3 seconds or so after starting. So I don’t think the ‘immobilizer’ is the problem, and I doubt the system forgot all its keys.
The worst that happens to these cars after a battery disconnect, to my knowledge, is having to recalibrate the automatic windows.
The link Tester posted also mentioned Subarus that lose their marbles. I’ve never seen that but perhaps this ‘feature’ isn’t by design. Maybe on some cars the system glitches and it scribbles over settings at random. Sometimes you lose your keys, other times your window settings, security settings, etc.
Still pretty boneheaded, if I you ask me.
First, I think Tester is correct, but the article he used for a reference may not be the best on this subject. But Tester, I do not understand the “No, keith” comment. Most people never consider the cost of some of the maintenance items when shopping for a new car, like CV joint boots, timing belts and now apparently the added cost of replacing a battery. The salesman is certainly not going to point these out. Even Consumers Reports seems to overlook these items.
If no wires were spliced on the car, and he just “plugged in” the stereo, and the battery was disconnected, then it’s very unlikely that a fuse has blown. It’s more likely that the issues you say you were having before are the problem. Sounds like you have a bad sensor somewhere. If so, you should have a trouble code stored in the computer. I would have someone plug in a code reader to check. Also could be as simple as a clogged fuel filter.
As mentioned above, look for any sign-age in the engine compartment near the battery warning about removing the radio. Check your owner’s manual too. And suggest to phone up the dealer, ask to talk to their service dept folks, and ask them if removing the battery and/or the radio can have this effect on the year/make/model of your car. They’ll know right away I suspect, and should be happy to tell you if this is a known issue with a simple phone call. I’ve heard of this happening to the radio – removing the battery makes it impossible to use the radio. It is a theft deterent. Steal the radio, sure, but it won’t ever work again without the re-programming code. But I expect removing the battery can cause similar mayhem with some cars too.
If you do need to remove the battery, there is probably a procedure that can be done to prevent this from happening, but you have to do it before you remove the battery. The service guys at your dealer should know one way or the other.
Removing the battery can also have this effect on older cars, but not by design. A power disruption can confound and confuse and even ruin the sensitive computer circuits in cars. The way to prevent this is to make sure the circuits are powered down as much as possible before removing the battery. It is very imporant when removing the battery to make sure the key is in the “off” position. Best to have the key in your pocket when removing the battery. And everything that is possible to turn off should be off. The radio, the lights, etc. Make sure everything is off first. Then remove the NEGATIVE battery cable first, before removing the POSITIVE. Same goes when installing a battery, except to connect the battery leads in the reverse order. Everything should be off, key in your pocket, connect the POSITIVE first, then the NEGATIVE.
There are similar restrictions on putting the car in “TEST” mode too on some cars. (TEST mode is used to set/check ignition timing, etc.) You have to follow the manufacturer’s shop manual. Some cars, the engine has to be “off” before changing to TEST mode. Otherwise the ECM can be damaged. Other cars, doesn’t matter.
I expect whatever the problem is, it should be fairly simple to resolve, but if this forum doesn’t get you back on the road, you’ll probably have to get someone experienced in working on your make/model to help.
my car did the same thing. the weird part is i unplugged the new harness from the radio and my car started.