Clicking relay-type sound after starting cold engine

[draxcam]

I have an S40 Yr 2000 1.9T. I get a combination of sounds and dimming lights when I start a cold engine and only after engaging the gear to either D or R. The sound resembles that of a relay clicking along with the momentary sound of a small motor purring. Also, coinciding with the click and purr, all lights (interior and exterior) experience a dimming effect for the duration of each click/purr interval. It seems to be something electrically related. It definitely is coming from the driver side, somewhere in the vicinity of the ECM but it's difficult to pinpoint the actual location as the car must be in D or R before you start hearing it. It definitely disappears as soon as engine temp rises to some predetermined temp. Any advice would be greatly appreciated.