New Tic-Toc-Tach

[Glen63]

I while ago, when I was feeling more flush, I bought a new Tic-Toc-Tach for the Charger. Its the one option the original owner did not spec, well that and the Hemi unfortunately !!

Anyway final got round to sorting all the gauges at the weekend and fitting the Tic-Toc-Tach. Clock works great ! The rev counter is working, but only seems to start picking up the signal when engine is reved up, then it starts reading, but reading low revs

I have connected the Positive to the fuse board and the signal wire to the negative side of the coil.

Anybody got any ideas what I might have done wrong ? I cannot see any adjustment on the rear of the Tic-Toc-Tach