This is for an Audi 80 but everything should be the same.
http://s2-audi.co.uk/workshop/80_abc/80abc.htm
It will just be a minicheck module.
Your oil pressure sender is 2.5 bar and has a grey/ white wire. It goes via a couple of connectors to pin 4 of T14 (white connector) on the rear of the instruments.
T4/h is in the engine bay on the right side (driver) - I'd check there first