Bronco, Pickup & Van Series (Gasoline Engines)

The tachometer on Bronco and Pickup can be used on 6-cylinder or 8-cylinder engines. Tachometer terminals "B" (12 volts), "C" (coil negative) and "G" (ground) are connected when used on 6-cylinder engines. A fourth terminal, "8" (ground), is grounded through wiring harness for operation on 8-cylinder engines. See Fig 1.

Fig 1: Tachometer Wiring Schematic (Gasoline Engines)
Courtesy of FORD MOTOR CO.
Check fuse and replace if blown. Check for loose wiring connections in engine compartment or at instrument cluster. Secure where necessary. Disconnect negative battery cable. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Check resistance and voltage using a Volt-Ohmmeter (VOM).
Check pin No. 2 of instrument cluster harness connector "B" for resistance to ground. Reading should be one ohm or less. See Fig 2. Check pin No. 3 of instrument cluster harness connector "A" for resistance to ground (8-cylinder), or open circuit (6-cylinder). Reading should be one ohm or less.

Fig 2: Instrument Cluster Harness Connectors "A" & "B" Terminal ID (Gasoline Engines)
Check pin No. 9 of connector "A" for resistance to negative terminal of ignition coil. Reading should be one ohm or less. Connect battery and turn ignition on. Check voltage at pin No. 13 of connector "A". Voltage should be 12 volts. Turn ignition off. Disconnect battery.
If readings are not as specified, problem is not in tachometer. Check wiring. If readings are as specified, check for loose or missing cluster connection clips. Check for damaged printed circuit. Reseat or replace missing clips. Replace printed circuit as necessary. If connection clips and printed circuit are okay, replace tachometer.