Our 10 years old VOSS electric oven model IEL 671-OT (conventional + convection) makes a loud and fast clicking sound when cooling down. It starts usually around 5 minutes after being switched off and will last until it is completely cool.
You can stop the sound for a period by simply turning the oven on and off again. After a few minutes it will start again though. Then you can stop it again by turning it on an off and so forth, until it eventually stops.
When the noise is sounding, the light in the clock display is considerably weaker than normal, around 50%. It regains the normal brightness immediately if you turn on the oven (which stops the noise) but will again go low when the noise starts.
I guess the sound comes from a relay, but I have no idea what the relay does and why it clicks.
I often fix stuff myself and don't mind disassembling the oven, but I would like to get a few ideas first, if possible.
UPDATE: Here is a short video where you can both see and hear the problem. Note how the dimming of the display is related to the clicking noise. In thise case the oven only reluctantly turned on when I pressed the switch, this is quite unusual. Normally it starts without problems and then the noise disappears.