Ford Repair Questions? Ask a Mechanic for Answers ASAP
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At the back of the cluster check the Light Green/Yellow (LG/Y) wire from fuse 8, terminal 1 to verify it's hot at all times. Check the White/Purple (W/P) at terminal 3 from fuse 18 and verify it's hot when the key is in the run position. Check to see if the Antilock Brake System (ABS) light is on. If the ABS light is on, start with that first. Pull codes to see if there is a Vehicle Speed Sensor (VSS) code. If OK, at the 12-terminal connector at the back of the instrument cluster, check for a good AC voltage signal between the RD/PK pin 4 and LG/BK pin 5 wires. The higher the speed, the higher the voltage. If the AC voltage signal increases with speed as it should, verify good power feeds on pin 1 LG/Y and pin 3 WH/VT and good ground on pin 2 PK/OG. If all is OK, but there is no speedometer operation, replace the instrument cluster.