Originally Posted by ah-kay

Make sure you have a FULLY charged and good battery and do the followings with a DMM:

1) With the car running. Check the voltage of the battery terminal. It should be normal 13-14.4V. This verifies the alternator is working.
2) With the car off and all lights, radio off. Remove key. Disconnect -ve terminal and measure any current draining the battery. It should be mininal < 500ma. The residual current is for clock or alarm etc.
3) If it draws a lot of current then go the fuse box and remove each fuse then measure the current across the fuse terminal. Most should have 0 current, except the fuse to the dash (it should be small also ).
4) If there is a massive short somewhere then there may be a burning smell.
5) If there is a short then the fuse would blow unless the fuse is over-rated.
6) I have resolved a lot of shorts in this manner.

Good luck.