Marker lights relay?

[Hendog]

Not my car. My NIL has a 996 C4cab on which the driver side marker lights come on when he runs the car. When he turns on his head lights the remaining marker lights come on as normal. Is there some sort of relay for each side of the car controlling the lights? BTW the driver marker lights stay on when he shuts off the car and will remian on until he removes the key from the ignition. Any ideas?