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Volvo 850 intermittent but rapid battery drain

My 1996 Volvo 850 has a relatively new battery but every few weeks it will go completely dead. A typical situation is this: the car will start fine and we will go to a restaurant but when we come out the battery is so dead that the digital clock is off and the radio pre-sets are lost. The shop has done a lot of diagnostics and replaced the alternator but the problem persists. They have determined that the battery is fine and the current drain when the car is off is within normal specs. And, yes, they have disconnedted the light in the glove box. They have done everything they can think of but because the problem is so intermittent it is proving impossible to track down. Any suggestions would be welcomed.

When this happened to my mother’s car, it was a door light switch that wasn’t turning the interior lights off if the door wasn’t closed all the way. In my wife’s car, when this happened, after several tries, I replaced the fuel pump relay and the problem hasn’t happened since. Relays can hang up (stay stuck in the on position), and if it’s something like the fuel pump or AC clutch, or anything else that could be on but not be obvious to you, you won’t notice it. Some of those things have a high electric draw, and can also be intermittent. Good Luck.

It seems to be an intermittent connection causing occasional battery drain. One of the best places to start is looking at the wiring that goes through the door jamb. Often times these will get wear spots and cause a short that should blow a fuse, but may not.