the glowing effect of my fireplace wont work?

I have a electric fireplace, the heaters are at the bottom and on top there's a plastic replica of charcoal, under it there are two red electric bulbs to make the charcoal look as if it's burning and two metal disks that should go round giving the sensation that there are actually flames glowing in the charcoal. The disks are not going round anymore, there haven't been doing it for quite a while now, there are no electric wires attached to them, they're only attached on a pin and when the fire place starts getting hot the disks should start going round. Can you help?