The dimmer circuitry (from the '95 960 manual) is a little baffling to me. THere is the dimmer wheel on the dash that is connected direct to and only to an item on the rear of the inst cluster called RHEO. this in turn is connectd to the bulbs that dim. I can only assume that the "RHERO" is a solid state device that gies a variable voltage output depending on the dimmer wheel setting. A possible source for your flickering could be a loose connection at the rear of the inst cluster (top left side) where the dimmer input and variable voltage output and ground are connected.
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'61 122 '67 122s '76 245 '81 245 '90 745 '95 960 (not counting parts cars)