Locate the wiring to the rear lights of the vehicle (usually on one side) and select a suitable point at which to mount the By-pass relay and make the necessary relay and 7 core cable connections. Connections must be made to conductors carrying a 12 Volt supply to the bulbs.. The 7-way smart bypass relay does the job of translating these signals and is a simple in-line fit between the towbar wiring and the vehicle loom. The fitter need not have an in depth understanding of the "multiplexed" system - the smart bypass relay's inbuilt microchip does all that.
To correctly wire the tow bar and bypass relay, you need to have a wiring diagram that shows the components and his connections. An example of such a diagram looks like this: The diagram above shows how component connections are made conceptually.. Installation and electrical wiring connections -for a universal TEB7AS Bypass Relay for a 7 pin trailer socket. If you would like to watch the Towbar install.