Hi my brother has a 1995 Audi Coupe
There seems to be a fault with both the temp gauage and fuel guage they read ok then go to zero and are all just everywhere really

Anyone have any ideas as to what it might be ???

Thanks
Also anyone know where the diagnostic plug is ???

 

95 Coupe? You must be from the other side of the pond! I would say it has to be a connector on the dash. Both VW and Audi have a history of intermittent dash gauges and indicators. The simple solution is to take the dash cluster out and reconnect all the connectors a few times. If you have access to Stabilant 22A add some to the contacts. If that doesn't help then you will have to whip out the factory service manual to see where both gauges have a common ground or the +12V terminal.