Problem solved........Tech support just got back with me. Here is what they said.
Hello Brian
The wiring with the pressure switch is a option, the negative terminal is connected to ground OR a normally open oil pressure switch.
You may connect the hour meter negative terminal to the same engine pressure switch if it functions as described in the instructions. If the pressure switch used on the dummy light is normally open (no electrical signal), and closes when the engine is running, than this pressure switch can be used with the hour meter. The purpose is to have the engine hours count when the engine is running not when just power is provided.
Thank you,
Marcin Maleszka
Technical Support Representative
Veethree Electronics & Marine LLC
I hope this helps anyone else with the same question. B