Radio and the doors

OK, I know this is totally unimportant, but when I dropped this info into another thread, I was told I must have a broken wire, but I now think that is not right.

56-reg Octy estate. I park, stop engine, put Stream mp3 radio on. Wait for woman to stop gabbing and climb aboard. If she does this within a second or three, the radio stays working fine and I don't miss my winning lottery numbers. If, as usual, the gabbing goes on and on and sweat pours off me as I watch the traffic warden marching swiftly forwards, I hear a relay go somewhere behind the dashboard. After this relay, when a door is opened the radio switches off and back on a few seconds later.

Unimportant, but weird. Just like the way the radio doesn't light up when you switch it on.

On a positive note, I've at last thought of a reason for the keyfob put all the windows down option. If I park and drop women at Matalan and give them a key in case my long walk to an interesting shop takes longer than them, they are not forced to sit there with all the doors open when the sun comes out. Hold down the button and they go alfresco. Not as good as an old Land Rover with air-con and door handles by lever, windows by winder and bonnet lock by optional padlock, but still a step in the right direction.