Audi VW Multi Purpose Relay - Rein 4H0951253

Product Information

A multi-purpose relay is an electrical switch that uses a small electrical current to control a larger current electrical circuit. The function of a relay is to activate various systems or functions that use a high electrical current without requiring high-current wiring directly running through the switchgear or ECU. The relay consists of a coil and a set of contacts. When a small current energizes the coil on the low current side, it creates a magnetic field that flips the switch back and forth, closing or opening the contacts and completing or breaking the circuit that powers the high-amperage device.

Multi-purpose relays are generalized relays that can run a number of different types of systems, such as fuel pumps, cooling fans, lighting, HVAC components, and windshield wipers just to name a few. This is why you will notice a multi-purpose relay may be listed for several different applications within a car, or the same application across multiple vehicles.

To diagnose a relay, you can energize the low current side using a basic 12v signal. You will hear the relay clicking. If the click is inconsistent or dulled, it might not be making a good contact. When it clicks, a multimeter should show continuity and near-zero resistance between the high-current contacts. If not, then the relay may be bad. Basic multi-purpose relays are very simple devices, so they don’t usually fail. However, if the relay has been subjected to extreme temperatures, or weather exposure, or is very old, never rule out a bad relay causing problems in your electrical system.

• System Failure: Several systems use multi-purpose relays to power them. When a relay goes bad, those systems will intermittently work or fail. A proper electrical diagnosis with a multimeter, or swapping the relay with a known good one is the best way to fix a failed relay.

About Rein

Founded in 2007, CRP Automotive introduced the Rein Automotive line of OE-quality replacement parts to the aftermarket. And in just two short years, Rein Automotive has become very popular among both warehouse distributors and professional repair technicians. Rein is the German word for “pure”, and has come to be synonymous with quality in the automotive aftermarket. A true dealer alternative.

The Rein brand includes a growing number of “better than OE” parts for selected applications. These parts address known weaknesses and premature failures of factory parts. Many of these replacement and service solutions have been developed with the help of our Innovation Council, a hand-picked group of experienced professional repair technicians and shop owners throughout North America.

All Rein Automotive OE-quality parts are backed by the CRP Automotive standard, and are backed with a ISO 9001:2015 quality management system certification. Each year, CRP Automotive ships thousands of Rein Automotive brand products. And with widespread NAFTA market distribution through strategically placed warehouses in Cranbury, New Jersey and Puebla, Mexico - OE-quality products like Rein Automotive are delivered to customers both faster and more cost-effectively than ever before.

In 2017 Rein partnered with FCP Euro in competing a W204 C300 AER car for the 2017 season. The partnership focused FCP Euro to dive deep into the Rein catalog offering, and hundreds of new products were added and integrated into our catalog. Hundreds of new packages were created not only using the full part pine up of Rein products, but also the entire family of CRP products like Pentosin.

Rein is also an innovative brand, winning numerous trade awards — including multiple new product innovation awards at the annual AAPEX trade show.