The adapter VAS 5566 is required in conjunction with vehicle diagnosis, testing and information system VAS 5051A/B and multimeters V.A.G 1526/1526A/1526B/1526C for simple, quick and secure detection of the various electrical/electronic signals from components, such as: - Radiator fan actuation for vehicles built on the basis of PQ 35 and PQ 46, etc. The connectors are decoded and are thus compatible with a number of 4-pin connectors. Use of the adapter is described in the relevant workshop/technical information.