I have started to install my 3 gauges, pillor mount (Bully Dog). No instructions sent with for install. When installing EGT gauge I have the thermo coupler wire, Yellow and Red with electrical ends already attached, and a red and black wire with loose ends. The back of the gauge has + and - post. It I slip the thermo wire on to post, the yellow connector matches the + side of gauge and Red connector matches the - post. This dose not seem right. There are no other post to connect power to gauge. Also when installing pillor, where and how do you get wires to to below the dash (93' chevy)?

Go to the gauge manufacturer's web site and search for install instructions. They usually have them. I know Isspro does.

Through the firewall, there's already a hole with a plug if you look by the wires that are passing the firewall.

That is the correct wiring for that connector. I have the same style, Red is -

I got a hold of Bully Dog yesterday and they said the gauge did not need a power wire. The Red and Black stray wires must go to the light wire.