Wiring novice needs help with autometer tach

[Paul Reveres Ghia]

 Evening folks,

I have just installed a new loom in my Ghia (it's a 59 Coupe) and I am now adding in the extra bits and pieces I need- I have very little experience with wiring and am kind of learning as I go along and from looking at the OG wiring diagram-



I am quite pleased with how much I have learnt so far and how I am now beginning to understand how it works!

What I can't work out is....

On the diagram from the tach it has a ground going to the engine which is where it claims the battery ground should be? Mine is going to the old battery clamp bolt in the engine bay as the battery has been relocated under the seat-

So my question is... Can I just ground the tach (& the battery for that matter) to the body shell of the car in the same way all of the lights are earthed??

oh, and also, Which is the positive terminal on the ignition switch that I need to connect the tach to??

Thanks in advance for your help?

[TexasTom]

Yes, ground the tach to a good, clean ground source to the body. Make sure the ground strap from trans to body is in excellent order!
Attach the tach power wire to the post on your igi nition switch marked "15" ... that's ignition power (normally black).

Take care,
TxT

[Paul Reveres Ghia]

Perfect, Many thanks