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This page gives technical details of various OEM electrical relays and controllers that may be useful for wiring projects in your .:R32.

The control numbers referred to are printed on the end of the relay casing and are visible when the relay is plugged in.

These relays are, of course, all designed and tested to be used in the car environment. They all plug into the standard VW relay sockets.

At the bottom of this page, I have also included a list of the Repair Wires required to wire up any additional Relay Sockets that you add into the Additional Relay Plate, located under the dash.

Part number 141 951 253 B

This is a SPST "normally open" load reduction relay. This is one of the most common relays used on VW's.

Please note, this relay has now been superseded by VW a few times recently. All of the following relays operate in the same manner as the original "53" Relay:

8D0 951 253 A with the control number "373"

8K0 951 253 with the control number "643". Note that the pins on this version relay are only labelled 1,2,3 & 5, unlike earlier relays which had 86, 85, 30 & 87 respectively. Also note these new numbers bear no relationship to the relay socket numbers that the pins plug into!

4H0 951 253 A with the control number "645". Note that the pins on this latest version relay are also only labelled 1,2,3 & 5 as per the "643" version. Note again that these new numbers bear no relationship to the relay socket numbers that the pins plug into!

Part number 191 927 841

This is a SPDT relay. It is similar to the famous generic "Bosch" relay with switching output between 87 and 87a terminals.

It also has a diode mounted in one of the inputs which may be useful in some applications.

Part number 431 951 253 F

This is a SPST "normally closed" load reduction relay.

Part number 431 951 253 G

This is a SPST "normally open" load reduction relay, however it also has an internal diode included between terminal 86 and 85 (relay coil) circuit to prevent voltage feedback (and clicking noise).

Part number 1C0 941 597

This acts as a "latching relay". It is actually an electronic control unit but with the standard relay pinouts.

I have found this one very useful to latch the signal from the "momentary action" OEM switches I have used on various projects. It will basically convert a momentary action switch into an on/off switch.

It also has the feature of resetting if voltage is removed from it, such as when switching off ignition. This then automatically turns off anything you may have left on to prevent a possible battery drain, for example, footlights.

This relay is originally used on Right Hand Drive New Beetle and New Beetle Cabrio to control the operation of their headlight flasher stalk. Due to a lack of space between the steering column switch and the central dash, the flasher stalk only pulls towards the steering wheel, so requires a "latching relay" to lock on the high beam headlights when required.

Terminal functions are as follows:

1 = Not used.

2 / 30 = Power supply for the "latched " Output.

4 / 31 = Earth

5 / 56 = This terminal must have 12V for the relay to remain "latched". The relay will return to an "unlatched" state if 12V is removed from this pin.

6 / LU = Momentary Pulse Input to latch/unlatch relay. This is the connection from your momentary switch Output.

8 / 56a = "Latched" Output.

Basic operation of the "434" relay connected to a momentary action switch.

If you press the switch, a momentary pulse is supplied to the relay Pin 6

The relay will "latch" from this signal only if there is also a voltage at Pin 5 of the relay.

When the relay latches, voltage supplied to Pin 2 of the relay will output through Pin 8 of the relay.

If you press the switch again, the momentary pulse will "unlatch" the relay.

If you remove voltage from Pin 5 whilst the relay is "latched", it will "unlatch"

For example, if you connect 15+ (Ignition) voltage to Pin 5, then the relay will only latch whilst the Ignition is ON. If you press your switch with the Ignition OFF, then nothing will happen.

If the item is switched ON whilst Ignition is ON and then you switch OFF the Ignition, your item will switch OFF as well. If you turn Ignition back ON, the item will remain OFF until you press your switch again.

This relay can also be utilised to simply operate the coil of another relay in a circuit. Refer to the links for Flapper Switch and Audi LED Footlights with On/Off Switch for examples of the wiring involved.

VW sell a Clip-in Relay Socket that locates in the square holes in the Additional Relay Plate under the dash of the .:R32.

The 9-pin version is 443 937 527.

This is the version used that will accept all the common relays noted above.

The photo below shows how to unlock the relay holder to allow the terminal pins to be withdrawn. Note the position of the purple lock in the photo - all four sides have to be released like this:

There is also an 18-pin version that takes up two adjacent vacant locations with Part Number 4A0 937 529 .

This version is commonly used when you also use a "double relay", such as the Multi-Function Steering Wheel Control Relay etc.

The photo below shows how to unlock the double relay holder to allow the terminal pins to be withdrawn. The locking procedure is totally different to the single relay locking mechanism:

Terminal Pins

If you look at the Relay Plate Mounts, you will note there are three different size terminal pins that they use.

The VW Repair wires for the different terminal sizes are:

Small

Terminal socket numbers 1, 3, 7 and 9.

1.0mm² = 000 979 133

2.5mm² = 000 979 225

Medium

Terminal socket numbers 2, 5 and 8.

1.0mm² wire = 000 979 135

2.5mm² wire = 000 979 227

Large

Terminal socket numbers 4 and 6.

0.5mm² wire = You can buy bare terminals from Porsche - Part Number 999 650 330 00

1.0mm² wire = 000 979 114 (or you can buy Porsche bare terminals 999 650 103 12)

2.5mm² wire = 000 979 212

I have quoted metric VW wire sizes above. Here are the approximate US equivalent wire gauge sizes:

0.5mm² ~ 20 gauge

1.0mm² ~ 16 gauge

2.5mm² ~ 12 gauge