Chrysler Repair: blinking exterior and interior lights:, lighting circuits, dashboard light

Question
Hello, I have 2004 Sebring 4dr 4cl 2.4L. When engine is on
all lights of the car - exterior (including head), interior
(dashboard light- when on, mileage digits, radio) are
blinking. Frequency slightly depends on engine rpm - it increases just a little bit at higher rotations. Battery
shows 12.4V when engine is off and 14.3 on 800 rpm after a
trip. I would appreciate if you help me to get rid of this
blinking as i think such voltage jumping can kill electronic
modules of the car . Thank you.  

Answer
Hi Alexander,
Those lighting circuits are on separate fuses so it is probably not related to the + side of the battery. Rather I would focus on the return path to the battery - post as the place where you probably have a loose wire connection. There is of course the - post of the battery itself where you could check the clamp to be sure it is tight, and the wire/clamp interface to be sure it is in good shape.
The battery is mounted in the left front fender in front of the wheel housing so you could turn the steering wheel far left for better access to that. While you are there, make sure the + post clamp is also tight.
The other ground wire runs from the negative battery post to the front of the left strut tower in the engine compartment, so check that connection as well. That is the main body metal ground point. Several interior light and exterior light devices ground to the body metal inside the cabin, on the panel in front of the driver's side door opening, several inches above the floor and maybe a foot in front of the opening. You should find a screw that has several black wires with eyelets on them that is fastening those wires to the metal surface of the panel. This would be near the drivers lower left leg, to the left of it. Check that bolt to be sure it is tight and that there is no corrosion between the eyelets and the body panel metal.
Ideally you will find a loose connection at the battery, the strut tower, or the panel in the cabin.
Let me know if that doesn't solve the problem. If not, do specify exactly which exterior bulbs beside the headlamps are blinking, and which are not blinking.
Roland
PS Please 'rate' my answer. Thanks