Another electrical mystery

GM vehicles have a feature called Retained Accessory Power (RAP) that allows certain electrical accessories, such as the radio, to stay on for a short period of time after the engine is turned off. This is done to prevent the accessories from turning off suddenly, which could cause data loss or other problems.

The RAP feature is typically set to stay on for about 10 minutes after the engine is turned off. However, in some cases, the radio may stay on for longer, even after the doors have been opened. This can be caused by a number of factors, including:

• A problem with the RAP switch. The RAP switch is a small switch that is located in the driver's door. It tells the car's computer when the door is open or closed. If the RAP switch is faulty, it may not tell the computer that the door is open, which will keep the radio on.

• A problem with the body control module (BCM). The BCM is the computer that controls the electrical systems in the car. If the BCM is faulty, it may not be able to turn off the radio properly.

• A software problem. The software that controls the RAP feature may have a bug that causes the radio to stay on.

This is a weird setup to me. I believe that when you turn off the key all electrical things should shut down. If you want them on when the engine is off, then turn the key to the accessory position. That’s what it’s there for. But I’ve adapted to GM’s way of doing things.

Then, after getting the van back from the engine transplant, the radio no longer turned off when I opened the door. I had to turn it off myself. Hmmm, okay, so the RAP switch? The BCM? Something reassembled incorrectly? Sigh. So I adapted to that new reality.

Today, out of the blue, with no intervention from me or anyone else, it reverted to the GM standard way of doing things. Go figure.