It is NOT possible unfortunately to install the Eberspacher Easystart PRO controller with an earlier generation D2 Airtronic heater. The harness upgardes you have seen on our website are to convert an older Eberspacher D2 Airtronic harness installation into a later harness to allow easy installation of the newer generation Eberspacher S2 D2L or S3 D2L heater without the inconvenience of renewing the full vehicle or boat harness.