Tachometer and wiring

[SteveJ]

21 minutes ago, AnvilZ said:

@Zed Head I went back and found the 71 wiring diagram I used from the 1971 FSM Supplement and it seems to show the same thing as EuroDat's 72 diagram. If it is accurate I am still wondering how the car can start with the B/W to the Ballast being switched out of the circuit in START assuming you had that wire "swapped" (connected to Coil +)

Not to dwell on that issue too long, but I think this is what was confusing me back when I did the wiring on my car. 

I have a feeling that it's wear on the contacts on the ignition switch allowing bleed over somehow. Maybe I'll run a test at the switch some day.

[Zed Head]

It would be interesting to see when the part number changed for the switch if it did.  1976 is definitely a different diagram, I think.  

Edited August 21, 2021 by Zed Head

[Dcreech0]

1 hour ago, cgsheen1 said:

Dcreech, I'd like to see a pic of the rear of the tach with special emphasis on the loop...

 

 

[cgsheen1]

Well, the steel "U" around the wire doesn't appear to be damaged. 

(while I was still employed as a Journeyman Plumber I used an Amprobe. It had jaws that clamped around a wire so you could measure the amperage that a particular electric appurtenance was drawing. Very helpful with electric motors to see if they were operating within specs. The steel "U" that's bolted onto the back is like the jaws of the Amprobe. It actually contacts with another piece inside and "completes the circle" that makes it's function just like the Amprobe. It's "reading" the amp draw of the coil. I've seen some that have been damaged on the back which renders them incapable of sensing the current draw.)

I guess you have a bad tach. Probably some other electronic component inside that lost it's smoke.