Water pump shaft broke, fan came off, serpentine belt broke. Replaced fan clutch, water pump and belt. Started up and found that the tach no longer works. When I start, the needle goes to 2200 and stays there while running. When I shut down, the needle drops back to zero.

On the wiring diagram a dark green/yellow wire goes through a capacitor to the tach (no resistor). On the 8-cyl there is the same capacitor plus a resistor.

Where is the capacitor and what is the value?

 

Is the tach a stock in-dash type? If it is, I would imagine the capacitor is inside the instrument cluster somewhere. Good luck, Peace, Dave.

 

Thanks, Dave.
I think you are probably rightt. I'll look inside the panel tomorrow. Ford and Chilton don't give a clue as to its location.

 

I had an instrument cluster I had gotten off of evilbay years ago, w/ tach. (mine doesn't have it). Couldn't get the tach working even though it was supposedly plug and play. Knowing me, I took it apart, but I only remember vaguely there being boards inside. Good luck, keep us posted, Dave.

 

When my 91 f150 did that I replaced the tach with one out of the junk yard it comes apart pretty easy only cost like 6.00$