On my '89 it's circuit 1.  If I recall correctly, the ground is circuit 3. if you're looking at the instrument cluster from the back, that'll be the first and third circuits on the left respectively. I don't think the ribbon circuit changed drastically through the years. The design of the circuit is that all four of the illumination lights (including digital clock) are wired in parallel, so if one goes out, the rest will still illuminate. The ground is shared with other things in the cluster, like the turn signal flasher and headlight indicator, so if those are working, the ground is still good.

If the 85 is similar to the 89, and you're at a loss (and can decipher abbreviated German), the ribbon may have the circuit number and purpose printed on the ribbon itself. To see that, you'll have to disconnect the housing for the connector from the instrument cluster. It's just held in with plastic tabs. On the folded flap of the ribbon are very small printed indications of the circuit.

If I had to guess from your description of all the lights going out when the cluster was pulled, I'd suspect that something on the ribbon circuit itself has broken, either at the connector or somewhere on the left hand side while looking at the rear of the cluster. 

-Jarrett
89 Westy
On Dec 15, 2011, at 3:27 PM, jon durham wrote:

> Which circuit on the ribbon connects to the instrument lights? The
> lights do not come on.
> --
> �The greatness of a nation and its moral progress can be judged by the
> way its animals are treated� --Gandi