Underdash wiring question.

[Ross Maylor <rvmaylor@shaw.ca>]

Behind the dash and coming from the main wiring harness are 2 connectors with
3 black ground wires affixed to each.
On my wiring diagram it looks like one might attach to the back of the speedo
gauge and the other the tach. But I am not sure and do not have a car to look
at. If this is so where on the gauge do they ground and if not where ....?

Thanks
Ross Maylor
'58 BN6