Ground Circuits

WARNING: This page is about a different variant/trim than selected.

Turn ignition off. Locate PCM. See POWERTRAIN CONTROL MODULE LOCATION table. Using a DVOM, check continuity between ground and PCM connector pins. See IDENTIFYING PCM GROUND PINS table. See Figure and Figure. If continuity does not exist, repair open ground circuit as necessary. If continuity exists, go to next step.

IDENTIFYING PCM GROUND PINS

Application			PCM Ground Pin No.
Continental, Crown Victoria, Grand Marquis & Town Car			3, 25, 51, 77 & 103
Contour, Cougar & Mystique			24, 51, 77 & 103
Econoline
	4.2L & 4.6L		24, 25, 51, 76, 77 & 103
	5.4L		3, 24, 25, 51, 77 & 103
	6.8L		3, 23, 24, 25, 51, 76, 77 & 103
Expedition & Navigator			3, 25, 51, 77 & 103
LS			A24, A25, A26 & A27
Mustang			24, 25, 51, 76, 77 & 103
	3.8L		24, 25, 51, 76, 77 & 103
	4.6L 2-Valve		3, 25, 51, 77 & 103
	4.6L 4-Valve		25, 51, 77 & 103
Pickup
	F150 & F250
		4.2L & 4.6L	24, 25, 51, 76, 77 & 103
		5.4L	3, 25, 51, 77 & 103
	Super-Duty Models		3, 23, 24, 51, 76, 77 & 103
Ranger			24, 25, 51, 76, 77 & 103
Sable & Taurus			24, 25, 51, 76, 77 & 103
Windstar
	3.0L		24, 51, 76, 77 & 103
	3.8L		24, 25, 51, 76, 77 & 103

Touch negative lead of voltmeter to a good ground. With vehicle running, backprobe positive lead of voltmeter to each ground terminal. Voltmeter should indicate less than one volt. If reading is greater than one volt, check for open, corrosion or loose connection on ground lead.