Troubleshooting preparations

Switch off ignition.
Get radio security code from customer.
Disconnect battery ground cable.
Remove instrument cluster. See INSTRUMENT CLUSTER, REMOVING AND INSTALLING .
Using adapter wire 1598/8, connect test box V.A.G 1598 to 28-pin connector, terminal 1 on instrument cluster and disconnected 28-pin connector on wiring harness.
Reconnect battery ground cable.

Fig 1: Instrument Cluster Power Supply Troubleshooting (1 Of 2)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Fig 2: Instrument Cluster Power Supply Troubleshooting (2 Of 2)

Courtesy of VOLKSWAGEN UNITED STATES, INC.