[jmeckel]

There are many things that can cause the issue. You need to fully charge the battery, then take a good volt meter and check the voltage when the engine is running at high idel. Also use a good dc amp meter and start isolating things and check for a draw with the engine off and the ing. switch off. It could be low or no charge from you generator, bad battery, current draw from a restive short to ground (a damp cracked and dirty wire can do this), etc. If you do not have a good meter I recommend a Fluke, 77, 87, etc. They will not be affected by the noise on the electrical system when the car is running. I can make this statement as I have used them professionaly in very noisy and RF heavy electrical testing for 30 years. Also use a printed copy of the A electrical diagram to help you.