New holland Tachometer issue

[Harry in Ky]

Before getting all carried away with wires, circuits, grounds, and other complications try putting a voltmeter on the AC output of the alternator (the post that powers the tach) and see what it reads. Most other model New Holland tractors with alternator driven tachometers need to see around 8 volts AC or they don't work right. See what you have. The problem may well be the alternator, not wiring related at all.

 

[number two]

I would have thought that this tractor has a cable driven tach/hour meter?

 

[thclimer]

If you don't find anything by checking the connections, these documents might give you further insight.

 

[Backhoeman1990]

I think I found the problem, Mice
Had a good time behind the dash.

 

[alexpops]

Count yourself lucky it only impacted the tach.

 

[TractorTech]

That does look like a/the problem