00 Tach issue?

[trailhead00]

Good day folks, first time in a post. I have the 2000 ranger 2x4 trailhead. 3.0L and going on over 125k mi. My factory installed tachometer is starting to intermitantly drop to zero or will register low for the gear (5spd). I know by my Haynes it takes signals from the ECM but thats all it says. Can someone complete the puzzle? Thanks in advance.

 

[blacksnapon]

PINPOINT TEST G: THE TACHOMETER IS INOPERATIVE
CONDITIONS DETAILS/RESULTS/ACTIONS
G1 CHECK THE GROUND TO THE TACHOMETER
NOTE: 4 cylinder engine equipped vehicles are not equipped with circuit 398 (BK/YE). Disconnect the instrument cluster C216 and proceed to Step G2.




Instrument Cluster C216


Measure the resistance between instrument cluster C216-8, circuit 398 (BK/YE), and ground. (6-cylinder vehicles [3.0L and 4.0L engines] only.)


Is the resistance less than 5 ohms?
Yes
GO to G2.

No
REPAIR circuit 398 (BK/YE). TEST the system for normal operation.
G2 CHECK CIRCUIT 11 (TN/YE) FOR OPEN
Connect the EEC-V 104-Pin Breakout Box.

Measure the resistance between instrument cluster C214-15, circuit 11 (TN/YE), and EEC-V 104-Pin Breakout Box pin 48, circuit 11 (TN/YE).


Is the resistance less than 5 ohms?
Yes
RECONNECT the powertrain control module (PCM). GO to G3 .

No
REPAIR circuit 11 (TN/YE). TEST the system for normal operation.
G3 CHECK CLEAN TACH OUT (CTO) SIGNAL TO TACHOMETER



Measure the voltage between instrument cluster C214-15, circuit 11 (TN/YE), and ground.


Is the voltage between 5 and 8 volts?
Yes
GO to G4.

No
INSTALL a new PCM. TEST the system for normal operation.
G4 CHECK THE INSTRUMENT CLUSTER PRINTED CIRCUIT


Instrument Cluster

Measure the resistance between the tachometer and instrument cluster printed circuit terminals; refer to the following chart:
Instrument Cluster Printed Circuit Terminal Tachometer Terminal
C214-13 "B"
C214-15 "S"
C215-2 "G"
C216-8 "G" (6 CYL.)



Are the resistances less than 5 ohms?
Yes
INSTALL a new tachometer. TEST the system for normal operation.

No
INSTALL a new instrument cluster printed circuit. TEST the system for normal operation.