'65 Formula S Tachometer Help?

[dibbons]

I can't find anything in the 1965 Plymouth Factory Service Manual (in the electrical section) regarding the factory installed tachometer. I would like to know which bulb is used to light the face, and what the wiring setup is, any help would be appreciated. Thank you.

 

[4spdragtop]

Sorry i can't help but here's a link to a cool site with schematics. I know there could have been midyear changes so an updated fsm schematic may be out there.
1956 - 1965 Plymouth Wiring - The Old Car Manual Project

 

[dibbons]

I found a magnifying glass and was able to read the installed (burned out, of course) bulb on the socket of an orange wire: #57. I will assume that is what the factory specified. It looks like wire colors for the tach gauge hook up are yellow (hard to say) (with a female/rubber push on connector) and black (with a round circular brass terminal). Still need to find out which wire goes where.

 

[Big_John]

Page 8-107 in the FSM gives you the wiring.

 

[dibbons]

Got it, that page fooled me by listing it as for Models AR-1 and AR-2 (Belvedere and Satellite).

 

[Big_John]

Got it, that page fooled me by listing it as for Models AR-1 and AR-2 (Belvedere and Satellite).

Yea, it's same wiring colors across the board. I probably should have mentioned that. LOL.

If you go in the back of the FSM, there's all the specs. Page 17 and 18 gives you the bulbs.

 

[valiantwagonguy]

Here is a visual the cut (yellow,red,and black go to the cut wires in the harness and it all just plugs together

 

[RedFish]

If you took one of these OEM tachs apart you would find a piece of fiber board with 2 studs mounted in it. It could be dropped through the housing one of two ways. That's why the housing wasn't marked which is which. Notice the 2 studs are different lengths. The shorter is sender/signal.

 

[dibbons]

The two studs on the back/rear of my tach are exactly the same length. However, they are different colors. Looking at the back of the tach, with the lamp at the 12 o'clock position, the stud on the left is brass colored and the stud on the right is steel colored.

The stud on the left also has a flat round washer on it colored brown. At first I thought it was a fiber type insulating type washer, but now I'm not sure because it actually feels like it is metal.

The stud on the right had no washer. Now I remember removing it and the tab for the wire connection, of course, was between the nut and the body of the tach, so I suppose a washer is not needed there. Unless, of course, it fell off sometime in the last 50 years.

I do have the update circuit board that is sold to repair/update the operation of the tach (still in the box somewhere, I will be searching for it). It will be exciting to bring this tach back to life.