K: Tachometer Inoperative, Ranger and Explorer

K1 CHECK FUSE


^ Check fuse 11.


^ Is fuse OK?


Yes

GO to K2.


No

REPLACE fuse. If fuse blows again, CHECK for short in circuit.



K2 CHECK CIRCUIT 11 (T/Y) FOR VOLTAGE AT TACH TEST CONNECTOR


^ Start engine.


^ Measure voltage at tach test connector using 73 Digital Multimeter 105-R0051 or equivalent.


^ Is voltage between 0.3 and 0.6 volts (Explorer) or between 3 and 9 volts (Ranger)?


Yes

GO to K3.


No

Refer to Powertrain Management/Computers and Control Systems/Testing and Inspection. Testing and Inspection


K3 CHECK CIRCUIT 640 (R/Y) FOR VOLTAGE


^ Key off.


^ Disconnect battery ground cable.


^ Remove instrument cluster.


^ Disconnect instrument cluster connector C1.


^ Connect battery ground cable.


^ Key to RUN.


^ Check for battery voltage at instrument cluster connector pin C1-4 using digital multimeter.


^ Is battery voltage present?


Yes

GO to K4.


No

REPAIR Circuit 640 (R/Y). VERIFY tachometer operation.



K4 CHECK GROUND CIRCUIT RESISTANCE


^ Key off.


^ Measure resistance between instrument cluster connector Pin C1-1 and chassis ground using digital multimeter.


^ Is resistance less than 5 ohms?


Yes

GO to K5.


No

REPAIR ground Circuit 398 (BK/Y) or 57 (BK). VERIFY tachometer operation.



K5 CHECK INSTRUMENT CLUSTER PRINTED CIRCUIT


^ Visually inspect instrument cluster printed circuit


^ Is printed circuit OK?


Yes

REPLACE Tachometer. VERIFY tachometer operation.


No

REPLACE printed circuit. VERIFY tachometer operation.