Battery cannot hold charge !

I just bought a Sable 1999 GS, 3 days later the battery was dead !
Mechanic found out that the radio was draining it, so bought a second
hand radio to replace it, it seems to work fine. Two weeks later, battery
was dead again !
Should I turn off all electric accessories (fan, radio, heat...) before leaving the car. Anybody had similar problems ? Please advice.

How old is the battery? Most batteries are only good for about five years. I had this problem with my MG, it turned out the trunk light was not turning off when the trunk lid was closed. How is the radio wired? Can you turn on the radio without turning the key to the accessory or on position? Yes, you should turn off the radio and see if stops the problem. I always turn off all accessories before leaving a car. This way there is no competition for battery power between the starter and accessories when starting the car.

How old is the battery? Most batteries are only good for about five years. I had this problem with my MG, it turned out the trunk light was not turning off when the trunk lid was closed. How is the radio wired? Can you turn on the radio without turning the key to the accessory or on position? Yes, you should turn off the radio and see if stops the problem. I always turn off all accessories before leaving a car. This way there is no competition for battery power between the starter and accessories when starting the car.

The battery is brand new ! Since the incident I make sure that all accessories are turned off before I leave the car, and the problem seems
to be fixed. Still I thought by turning off the ignition, all accessories are off automatically as in my previous 3 Japanese cars. Unless American
cars are wired differently. Your inputs are very welcomed.

Does your radio stay on after you turn the key off and shut off when you open the door. Some radios have this option. These cars are known for problems with door switches. Maybe the radio is not shutting off with switch.

i do quite a bit of stereo installation, and it sounds like the accessory wire is crossed with your main constant, but this should also cause youre stereo to lose its memory everytime you shut off the car. is the stereo hard wired to the wire harness or is it connected with a converter?