Tach Question

[noruckus]

The tack on my Exp does not work all the time, not an issue but like having one, any ideas of where to look to fix it, like a connection on the engine, where could I find that or maybe something else to try? Thanks for any help.
Mike

 

[2000StreetRod]

tach signal

The source of the tachometer signal is PCM pin 48 (tan/yellow). From the PCM connector it goes to the engine main electrical harness connector. Then it goes thru two more connectors to the 16 pin instrument cluster connector C286 pin 15 (tan/yellow).

 

[2000StreetRod]

Message Center

The PCM generated tachometer signal goes to the message center as well as the instrument cluster. You might try disconnecting the C2009 (largest connector) message center connector to see if the message center is shorting out the tachometer signal.