Gone are the days of craning our necks to see blind spots or using paper maps to find our way – you can now customize your car or truck with these wiring diagram theories, to have a reversible camera display and GPS installed.
Next, installing a GPS that’s bolted into the dash as opposed to having wires everywhere.
During your installation remember that the power source is connected to one side of a coil and the ground to the other – when 12V is applied it creates a magnetic field that closes the switch.
Yes the grounds are necessary on the relays. The power source is connected to one side of a coil. The ground is connected to the other side of the coil. When 12V is applied across this coil, it creates a magnetic field that closes the switch above. Without the ground, the relay won’t do anything.