FAQ electrical kits

Here are a few questions and answers on electrical kits

An electrical kit is necessary to ensure there is a connection between the towing vehicle and the trailer, so that all the necessary lighting facilities (tail lights, indicators etc.) also function on the trailer.
What is a universal electrical kit?
A universal electrical kit is not designed for one certain vehicle and has therefore to be adapted to fit the respective vehicle, which can also mean more installation work. For this reason the cable lengths of the universal electrical kits are generously dimensioned, since depending on the vehicle, alterations may have to be made, for instance shortening, lengthening or re-laying cables. The lighting functions of the vehicle also have to be determined and connected with the respective cables of the universal kit by cutting-connectors. Universal electrical kits can be used for most vehicles, but one must bear in mind that universal electrical kits can as a rule not be used on vehicles equipped with a CAN data bus.

Universal electrical kits are available in 7- and 13-pin versions and are differentiated as follows:

  • Universal electrical kit for vehicles with Check-Control and
  • Universal electrical kit for vehicles without Check-Control
What is a vehicle-specific electrical kit?
A vehicle-specific electrical kit is one specially constructed with the right cable lengths and functions and usually equipped with original plug connectors. In the case of electrical kits with vehicle-specific connectors, simply remove the tail light connectors and lay the lead between them. This way you will have an optimal function and a safe electrical connection using the original connectors and contacts.

The assembly manual for a vehicle-specific electrical kit describes the fitting steps required for the respective vehicle and helps keep the fitting time to a minimum.

What is a 7-pin electrical kit?
A 7-pin electrical kit is sufficient to provide a trailer with the lighting required by law; it is delivered with a 7-pin socket. However, if additional functions are required, for instance controlling the trailer reverse lights, additional power in a camper (e.g. refrigerator) or for mounting a rear cycle carrier etc., this 7-pin system will not be enough.
What is a 13-pin electrical kit?
A 13-pin electrical kit is pre-equipped with an interface for additional power supplies and is delivered with a 13-pin socket.

Unlike the 7-pin electrical kit, the 13-pin kit enables the transfer of all lighting and additional functions. All additional functions, such as controlling trailer reverse lights, additional power in a camper (e.g. refrigerator) or for mounting a rear cycle carrier etc. are warranted with just the one connector.

What does a C2 indicator lamp do?
The law requires a C2 indicator lamp to monitor the flashing lights of the trailer and shows the driver if the trailer indicators are working.
The C2 indicator lamp must been within the driver’s field of vision, blinks in rhythm with the trailer blinking lights and so signalizes their function to the driver.
When does the acoustic indicator warning sound?
The acoustic indicator warning sounds in rhythm with the trailer indicator lights and so signalizes their function to the driver.
Advantages: No work on the dashboard necessary, less assembly time.
What is an electronic warning device?
Unlike the C2 indicator lamp and the acoustic warning, the electronic warning device signalizes the non-function of trailer indicator lights. A failure of the blinking lights is indicated to the driver by a double blinking frequency in the indicator warning system already installed in the vehicle.
What is Check Control?
The Check Control system, also known as light failure indicator or monitor, is a component of the vehicle electronics and monitors various functions of the vehicle when in operation, for instance full beam headlights, brake lights or rear fog lamp.

If the lighting fails the driver is notified either by an acoustic warning signal or an optical symbol; with a board computer digital information will be shown.

What do you have to observe with a Check Control?
To avoid damage to the vehicle electronics, the electrical kit for vehicles with check control has to be designed in such a way that the lighting functions are always tapped before the lamp testing device or generated via trailer module from steady plus.
When do you need auxiliary power supply?
With 13-pin electrical kits an extra cable kit will always be required if electrical consumers in the trailer have to be supplied (e.g. a refrigerator in a camper).
What are parking assistance systems, Parktronic, Park Distance Control (PDC) and Acoustic Parking System (APS)?
A parking assistance system helps the driver park by means of optical or acoustic signals.

With most electrical kits this parking assistance system is automatically deactivated to avoid any misinformation. This switch-off function can be regulated via the micro-switch in the socket or via the control device.

What is a micro-switch?
A micro-switch is located in the 7- or 13-pin socket of an electrical kit and controls the functions, such as trailer identification, switch-off of the parking assistance or activation or deactivation of the fog light on the trailer.
What is a CAN data bus?
If a vehicle is equipped with a modern CAN data bus (Controller Area Network), the information exchange within the on-board vehicle network is carried out on a digital basis and not, as is usual, on an analogue basis. To process these digital data and transfer the information required for the trailer operation the electrical kit must have a corresponding CAN data bus trailer module, so that all functions (reverse lighting, indicators etc.) required for the trailer can be controlled.

A vehicle equipped with a CAN data bus must almost always be activated for towing.

Universal electrical kits can, as a rule, not be used in vehicles equipped with a CAN data bus.

When does a vehicle have to be activated for towing?
In the case of modern vehicles, in particular those equipped with a CAN data bus, the vehicle almost always has to be activated for the towing function. Please refer here to the car manufacturer’s operation manual.

The activation of a vehicle for towing can, as a rule, be carried out by any qualified workshop.

Fitting and fitting time of the electrical kit
The fitting times given are non-binding reference values in minutes.

These specifications can vary depending on various influences, such as the experience of the fitter, the level of equipment or condition of the vehicle. In any case, the operation instruction manual of the vehicle (trailer) should be consulted before beginning with the fitting.

Towbars and electrical kits are safety components and should only be fitted by qualified personnel!

Follow us

You can reach us
Monday to Friday
from 8 am to 5 pm

Mail kundenservice-de-en@mvg-ahk.eu
Phone +49 (0) 2403 / 7902-60