Ground Circuits

Turn ignition off. Disconnect PCM 104-pin connector. PCM is located on right rear of engine compartment. Using DVOM, check for continuity between chassis ground and PCM harness connector terminals No. 3, 25, 51, 76 and 103. See Figure. If continuity exists, see POWER CIRCUITS . If continuity does not exist, repair open in affected ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS - F150 article in ELECTRICAL.