With the cluster removed on this car, let's take a second to identify some of the connections:

Speedometer cable

Oil line fitting

Small plugs for cluster accessories and lighting

Large primary plug

Not pictured are the wires and bulbs for the glow plug and seat belt light, and the spade plug for the clock. Keep track of which bulb went in which socket - the wires will be different colors. On this car the wire for the seat belt light was green and the glow plug bulb wire was blue.