Ground Circuits
Turn ignition switch to OFF position. Locate and disconnect Natural Gas Vehicle Module (NGVM) 60-pin connector. NGVM is located at front center of engine compartment. Check continuity between chassis ground and NGVM connector terminals No. 40 and 60. See Fig 1. If continuity does not exist, repair open in affected ground circuit. See appropriate WIRING DIAGRAMS article. If continuity exists, go to next step.