L: Tachometer Not Reflecting Engine Speed

L1 CHECK SUPPLY TO GAUGE


^ Turn ignition switch to OFF position.


^ Partially remove instrument cluster panel, as outlined, to gain access to the cluster connectors.


^ Turn ignition switch to the RUN position.


^ Using a voltmeter check voltage at Circuit 640 (R/Y) at connector.


^ Is battery voltage present?


Yes

GO to L2.


No

SERVICE Circuit 640 (R/Y) for open. RESTORE vehicle. RETEST
system.



L2 CHECK GAUGE GROUND

^ Using an ohmmeter connected to a known good ground, connect second lead to Circuit 398 (BK/Y) (except Ranger 2.3L) and Circuit 570 (BK/W).


^ Measure resistances.


^ Are resistances 5 ohms or less?


Yes

GO to L3.


No

SERVICE Circuit 398 (BK/Y) and 570 (BK/W) for open. RESTORE vehicle. RETEST system.



L3 CHECK TACHOMETER INPUT CIRCUIT


^ Turn ignition switch to OFF position.


^ Disconnect cluster Connector C1.


^ Disconnect ignition coil, or DIS.


^ Using an ohmmeter, measure resistance of Circuit 11 (T/Y) from ignition coil Connector or DIS Connector to cluster C1 Connector.


^ Is resistance 1.8 ohms or less?


Yes


GO to L4.


No

SERVICE Circuit 11 (T/Y) for open. RESTORE vehicle. RETEST system.



L4 CHECK CLUSTER CLIP TO CLUSTER CIRCUIT CONNECTION


^ Reconnect cluster Connector C1.


^ Using an ohmmeter check for continuity from the tachometer connector clips to instrument cluster printed circuit.


^ Is there continuity?


Yes


GO to L5.

No

REPLACE connector clips. RESTORE vehicle. RETEST system.



L5 CHECK PRINTED CIRCUIT


^ Using an ohmmeter, check each circuit listed below for continuity from gauge connector clips to cluster Connector J1.









^ Is there continuity at all circuits?


Yes

REPLACE speedometer/tachometer assembly. RESTORE vehicle. RETEST system.


No

REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.