How do I replace the gauge cluster lights on my 1982 300D turbo? Is it necessary to remove the entire instument panel, or can the clear cover (in front of the gauges) be removed for easier access to the bulbs? Thanks.

You need to pull out the whole cluster.
The easiest way, especially if you don't have the proper tools is to remove the driver's side speaker and push the cluster out with your hand.

On you particular vehicle I think there are only two bulbs.
One for each side on the top corners.
Just be careful when disconnecting all of the stuff from the cluster. You might want to write it down and double check everything before popping the cluster back in. Also, be careful with the speedo cable. Don't pull it out too far, you can stretch it.

Vin