Review on 🚀 High-Performance SAMDO Universal GPS Speedometer Boat Gauge with Odometer 85mm 160MPH – Ideal for ATV, Motorcycle, and Marine Applications by Kevin Griffin

I bought one and installed it on a 1967 BSA A65 bike. The answer to the question "does this speedometer work on positive ground classic cars" is "yes", it works. Simply connect the red wire to ground (+) and the blue wire to ignition (-). However, the backlight will not work if the orange wire is connected to the vehicle's headlight (-) circuit. The backlight can be permanently off when the orange wire is not connected, or it can be wired to be permanently on when the orange wire is connected to (+), or if you prefer you can use a separate switch install that connects the orange backlight wire to (+) . Important! Note that the GPS coaxial cable connector is live (-) and must be insulated so it does not touch (+) ground.