Faria Gauge Wire Identification

[Boats Bros]

Yes I read the sticky and the manuals within it. I need some help identifying the wires on the back of the speedometer gauge. Are these correct? I’m guessing the gauge always has power and ground and it toggles a ground with the power on?

A - Red - power
B - White - Ground
C - green - sender input
D - black - ground

[Boats Bros]

Bump, who knows these gauges inside and out?

[SilentSeven]

TechBeer might know.

They wrote up this page / https://www.planetnautique.com/vb5/f...-faria-gateway

[northernoak]

I replaced my failed Telefex gauges with Faria gauges this spring. On the speedometer I had 3 wires and the RPM gauge has 4.
This was my breakdown for wiring:
Blue - Gauge Light
White - Signal Input
Black - Ground
Purple - Battery

I put a probe on the wires to figure out which was my gauge lights and then turned the light switch on and off to find it. That narrowed it down to 3 wires. My boat has the keypad so I did the same thing to find the battery wire by punching in my code and making the gauges "live". After that I just assumed they used the universal ground color of black which then left my purple white wire as signal.

[TechBeer]

Hi Boats,

If there are 2 connectors on the back each with 4 pins then that is the Faria Serial Bus that is used a lot for gauges of this era. I'm on a plane so I forget the exact pin assignments but I "think" they are: 1. +5VDC 2. Data+ 3. Data- 4. GND or something close to that. The data is driven by the Faria Gateway and drives a stepper motor inside the gateway to move the needle. I know the smaller gauges work like that but not totally sure about the speedometer. I have tried by not able to decipher the exact commands on this serial bus. It might be similar to CAN but I could not figure it out. The back light is turned on by a serial command.

When I'm stationary I can probably add more.