[Tigers] Auto Meter tach for Tiger

[Rollright at aol.com]

Hello all,
 
Got the final parts in and started final assy. of tach.
 
People have advised me to apply  12 VDC to the tach to establish "0"  RPM 
point.
 
Try as I might, on the positive and negative terminals on the back of the  
tach, I get no movement (or pressure in either direction).
 
Can anybody suggest anything? What am I overlooking or doing wrong?
 
Best regards,
 
 
Jim  Armstrong
Mk 1A 382002083
LRXFE