The Delco Modulated Displacement Control Unit controls the number of cylinders in use (4,6 or 8) used by Cadillac in the 80's There are no spares anymore, so if you like to have your MDA control checked or repaired contact me. I have setup a test unit for this purpose. I had to repair my own MDA control unit. A functionality check cost you $20,00 plus shipping If the unit need to be repaired it will be about $65.00 (depends how many bad parts) plus shipping I'm located in California
/Bennie