When I turn up my stereo system in my 2004 dodge 2500 ,interior lights flash , door ajar light comes on , and my gages move ?

The door ajar switch is likely defective, it senses the door is open ad turns on the coutesy lights as well as alerts you to the fact the door is open and the key is on (door "ajar").

Door ajar switch problem more then likely or wiring issue . The BCM - body control module won't turn off interior light , let door lock because it think's the door is open . The door ajar switch is a input to the BCM .

The first thing would be to have it checked for DTC'S - diagnostic trouble codes . Also check with an enhanced scan tool to see if the BCM shows ajar switch data (open or closed ? Do you know about body electronics ?
Body Control Module
The various BCM input and output circuits are described in the corresponding functional areas indicated on the BCM electrical schematics. The Body Control Module functions include the following:
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A/C compressor request. Refer to Air Temperature Description and Operation

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Remote Function Control. Refer to Keyless Entry System Description and Operation

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A/C cooling Fan. Refer to Air Delivery Description and Operation

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Audio Delay Power. Refer to Radio/Audio System Description and Operation

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Exterior and interior lighting control. Refer to Exterior Lighting Systems Description and Operation

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Daytime running lights (DRL)

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Automatic lighting control

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Fog lamps

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Interior lighting. Refer to Interior Lighting Systems Description and Operation

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Battery rundown protection (Inadvertent Power). Refer to Interior Lighting Systems Description and Operation

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Chimes. Refer to Audible Warnings Description and Operation

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Key-In-Ignition

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Head Lamps On

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Seat Belt Not Fastened

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Turn Signal On

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Park Brake Warning

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Door Ajar Warning

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Check gages

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Gage control. Refer to Instrument Cluster Description and Operation in Instrument Panel, Gages, and Console.

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Instrument cluster indicator control. Refer to Instrument Cluster Description and Operation in Instrument Panel, Gages, and Console.

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Theft deterrent. Refer to Theft Systems Description and Operation .

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Engine coolant level sensing. Refer to Cooling System Description and Operation .

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Washer solvent level sensing. Refer to Wiper/Washer System Description and Operation in Wipers/Washer Systems.

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Key-in-ignition sensing. Refer to Audible Warnings Description and Operation in Instrument Panel, Gages, and Console.

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Seat belt use sensing. Refer to Seat Belt System Description and Operation .

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Brake fluid level sensing.

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Parking brake state sensing.

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Rear compartment interface. Refer to Power Door Locks Description and Operation

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Horn interface.

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Door lock interface. Refer to Power Door Locks Description and Operation

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Bulb Check. Refer to Instrument Cluster Description and Operation in Instrument Panel, Gages, and Console.

May l suggest you change the battery in the remote fob have this done by an auto sparky some fobs hold codes which must be saved good luck PAUL@ FIREFOX

You probably have a broken door switch., so the system thinks a door is open. Fairly common failure, easy and inexpensive to fix.

your pin switch on the door frame ,may have dirt or rust held on with small screw remove the screw and lift out the pin switch try clean it first.

One of your door jam switches is bad or is shorting out. Check in door jams for plastic switches.

you have a faulty auto alarm system have to have it tested

the same thing happened to my car (2004 impala ss) yesterday aug 23, 2010 in the afternoon..... al palicz 732-904-3663

One of the doors has pinched and it is not releasing the switch or plunger.

Turn the headlight switch anti clockwise until you hear a click

There is a feature to disable the interior lights when the doors are open for camping. (Turn the switch fully clockwise).