If you read my post last July I had the same problem.There are no wiring diagrams available for the Mk1 Aero.My heater controller under the dash was replaced and as previously stated there is an eight pin connector under the steering column that badly corrodes.
Being unable to replace the air con controller we have rewired the system with three relays and extra fan fitted.I had this all done professionally and am just explaining the basics.It all works better than originally.
Simon supplied the new condenser and pipe.
