dal documento che ti ho mandato (che deriva dal link, che non trovavo più, grazie Fire)

When both of the turn signal lights and the high beam indicator are on and the Digital Cluster is dark, there may be a problem with the ground wire. The wire leads from the cluster through a firewall connector into the engine compartment, to a frame ground.

Typical problems are:

1) The ground wire is broken.

2) The ground wire has a bad connection to the frame (under the drivers side cylinder head, near the firewall).

3) There's a bad connection at the firewall connector.



look at the a diagram of the wires leading to the digital cluster.
http://www.batee.com/corvette/dcrg/w...ng_diagram.htm


The Fix
The easiest fix for all three of these problems is to tap into the ground wire on the passenger side of the firewall and run a separate wire to another electrical ground. This can be connected to another ground wire like the one for lighting or the radio, or to a seat bolt, etc.

1) Run a wire from the D1/Black wire to a good electrical ground.

2) Run another wire from D3/Black with white stripe to a good electrical ground.

3) Run another wire from B1 / Black to a good electrical ground.


chiaro, no?