After about 3 days of sitting the battery goes dead in my 79. I did a current flow check with a multimeter on the 10 amp scale and had a reading of 1. When I pulled the courtesy fuse the reading went to zero, however then the radio would not work. If I pull either fuse, the radio or courtesy the radio quits. I took out the courtesy timer located behind the glove box and reading goes to .5. Any suggestions on how to fix this??