after market fuel pump wiring diagram | Cadillac Owners Forum Mar 12, 2013fuel pump wiring harness???? Installed a new fuel pump with sensor on my 1999 cad seville sts.. came with a flat oval 4 pin plug replacing the OEM square pin plug.. its color coded but does it mean its correct??? my OEM square plug wiring A purple B grey C black D Blk/white stripe. Cadillac Seville Fuel Pump Wiring Harness | Auto Parts Let the people with 12+ years of experience in finding and buying car parts help you find the best Fuel Pump Wiring Harness for your Cadillac Seville. We here at Auto Parts Warehouse want to make sure you're happy with your car part purchases.