2005 Chrysler 300 3.5 Was told computer is not sending out power to small wire that changes battery. Already replaced alternator. Will buying a reflashed pcm resolve those problems?

Computer controlled charging system .
300 what ? Chrysler ?

This answer covers:
2005 Chrysler 300 6cyl VIN "G" 3.5L SFI HO (72% of 2005 300's)
2005 Chrysler 300 6cyl VIN "R" 2.7L MFI DOHC (28% of 2005 300's)
2005 Dodge Magnum 5.7L engine

Alternator

Removal & Installation


WARNING - Precautions Section:
Disconnect negative cable from battery before removing battery output wire (b+ wire) from alternator. Failure to do so can result in injury or damage to electrical system.

2.7L Engine

1. Before servicing the vehicle, refer to the Precautions section.
2. Disconnect negative battery cable.
3. Remove alternator drive belt.
4. Disconnect alternator field circuit plug.
5. Remove B+ terminal nut and wire.
6. Remove 2 lower mounting bolts.
7. Remove alternator.

To install:

1. Install alternator.
2. Install upper bolt mounting bolt.
3. Install 2 lower mounting bolts.
4. Tighten bolts to 48 ft. lbs. (65 Nm).
5. Install B+ terminal nut and wire. Tighten nut to 115 inch lbs. (13 Nm).
6. Connect alternator field circuit plug.
7. Install alternator drive belt.
8. Connect negative battery cable.

3.5L Engines

1. Before servicing the vehicle, refer to the Precautions section.
2. Disconnect negative battery cable.
3. Remove alternator drive belt.
4. Remove bracket bolts.
5. Remove upper mounting bolt.
6. Raise and support vehicle.
7. Remove middle splash pan.
8. Disconnect alternator field circuit plug.
9. Remove B+ terminal nut and wire.
10. Remove lower mounting bolts.
11. Remove alternator.

To install:

1. Install alternator.
2. Install lower mounting bolts. Loosen install the upper mounting bolt.
3. Tighten lower mounting bolts to 48 ft. lbs. (65 Nm).
4. Connect alternator field circuit plug.
5. Install B+ terminal nut and wire. Tighten nut to 115 inch lbs. (13 Nm).
6. Install middle splash pan.
7. Lower vehicle.
8. Remove loose installed upper bolt.
9. Install bracket and bracket bolt.
10. Install upper mounting bolt and bracket.
11. Tighten upper mounting bolt to 48 ft. lbs. (65 Nm).
12. Tighten the bracket bolt to 40 ft. lbs. (54 Nm).
13. Install alternator drive belt.
14. Connect negative battery cable.

5.7L Engines

1. Before servicing the vehicle, refer to the Precautions section.
2. Disconnect negative battery cable at battery.
3. Remove alternator drive belt.
4. Raise and support vehicle.
5. Unsnap plastic insulator cap from B+ output terminal.
6. Remove B+ terminal mounting nut at rear of alternator. Disconnect terminal from alternator.
7. Disconnect field wire connector at rear of alternator by pushing on connector tab.
8. Remove alternator support bracket nut and bolt. Remove support bracket. See Figure 1.
9. Remove 2 alternator mounting bolts. See Figure 2.
10. Remove alternator from vehicle.

Fig. 1 Alternator Support Bracket - 5.7L engine



Fig. 2 Alternator Mounting Bolts - 5.7L engine

Send it to the salvage yard
27 Years old,let it go

Try charging the battery with a small 10 amp battery charger with the negetive terminal removed, remove the charger and let set overnight. Hook the battery back up the next day and see if the car will start. If so, the alternator is bad. Drive to your nearest parts store and they can check the alternator to be sure it is bad. or just skip my first step and just go to the parts store, they will check the battery and alternator for free.

It sounds like you have a loose wire. Go back and check all the connectors. I know it sounds tedious but with electrical you just have to trace wires until you find the problem.

That is a tough one. Alternators do not overcharge because the alternator is bad. They overcharge because the alternator CONTROLS are having problems. The charging system in your 2005 Chrysler 300 is controlled by the Powertrain Control Module (PCM) Your vehicle needs to be diagnosed by someone who understands how this system works.

Sorry about the $129....I would raise a BIG fuss about that if they told you the alternator needed to be replaced. Apparently, they do not understand how your system works. (It is very difficult to give a correct diagnosis if you do not know how the system works in the first place.)

Dirty connections or corroded cables. Clean and/or replace what you can on the + and - side. + to the battery and the +starter position, and especially the - from the engine to the ground The ground is VERY important to look at here, since it is a jump start that makes it go. Let us know.

you have a bad diod in your alt you can have this tested at auto zone they can test your diod on the car for free **** i know that is whats wrong

look under hood remove cover for relays and fuses , should be a main fuse link where pos cable from battery and a ground come together with a fusible link in between it might need replacing

You will have to get a new e c m ,computer,the voltage regulator for the alternator is in the computer( E C M ).