The harnesses are intentionally on the long side to accommodate installing the ECM in various locations. Simply cutting the harness and splicing it back together with butt splices is NOT recommended. Some of the wires carry signals operating at low voltage so a poor or corroded connection will cause a malfunction. Best to find a spot under the dashboard where a loop or two can be tucked away. Before attempting to shorten the harness contact Patton Machine or Affordable Fuel Injection.