If your Pump Mounted Driver (PMD) in your ChevyGMC 6.5L has called it quits like they so often do, then use a BD PMD. Pump Mounted Driver - located on the side of the 6.5L Chevy Stanadyne DS4 injection pump. Extension Cable to easily relocate your PMD Pump Mounted Driver - located on the side of the 6.5L Chevy Stanadyne DS4 injection pump The PMD Pump Mounted Driver - located on the side of the 6.5L Chevy Stanadyne DS4 injection pump is an electronic control module that is mounted to the side of the 6.5L Injection Pump. As with most electronics, they begin to fail when the heat in the surround environment becomes too much. The area which the pumpdriver is located is very susceptible to this harsh environment.When used in conjunction with the BD PMD Pump Mounted Driver - located on the side of the 6.5L Chevy Stanadyne DS4 injection pumpRelocation Kit, these cables make relocation a snap.