Introduction | 3B S2 | ABY S2 | ADU RS2

Electrical Wiring Schematics

Introduction to S2 Wiring

These pages provide some of the schematic information on the S2. This stuff isn't easy to get hold of, and there are some missing sections - particularly on the ABY engined S2 but I will annotate the almost identical ADU information as best I can to provide an initial view on the ABY schematics.

You will note that the source of the 3B Schematic is Norwegian, so I have provided the raw Norwegian and English annotated versions on the respective pages. The colour scheme on all the wiring diagrams is identical (thank goodness) as it is derived from the original German scheme which is listed below.


Code Colour
ro RED

Other things to note when trying to understand the wonders of S2 wiring diagrams are that there are three locations for relays.

  1. The main relay (and fuse) carrier located under the bonnet near the corner of the bulkhead on the drivers side
  2. The front auxiliary relay carrier is located below the dashboard, just above the drivers pedals
  3. The rear auxiliary relay carrier is located below the rear seat 

Furthermore, the numbering scheme for all of these relays does not rely on the traditional methodology and common sense that you would normally associate with our favourite German car manufacturer.

Its all a bit confusing at first, but here's a few simple pointers to sort out any potential confusion. The relays in the main panel are numbered 1 to 11. The relays in the front auxiliary panel are numbered 1 to 18 whilst the relays in the rear auxiliary panel are numbered 19 to 22. Each panel is shown in the associated figures. So there are actually two sets of relays numbered 1-11 which is insane...

The nomenclature that I use is M1-M11 for relays in the main panel and A1-A22 for the auxiliary relay locations. This avoids the confusion on relay positions 1 through 11.

However, the S2 schematics do not have any special numbering to sort out the mess. The method used on the factory S2 schematics to differentiate relay positions 1 thru 11 from the main and front auxiliary relay panel is quite simple though -

If the relay appears in the top section of the schematic like this, then the location is the main fusebox. However if the relay is drawn outside of the top section, like that, then the location is an auxiliary panel.

Click for better image

Click for better image

Click for better image


There is similar confusion with respect to some of the fuse locations on the S2 wiring schematics. As far as the schematics are concerned, fuses at locations of S23 and above are located in the 'auxiliary fuse panel', but they are in fact located in the main fusebox with the rest of the fuses in the vast majority of cases. This applies to fuses S23-S30 in the 3B Coupe and to fuses S23-S32 in the ABY cars. It is doubly confusing because the fuse numbering scheme changed for the ABY motors such that the two spare fuse positions in the 3B fusebox are deleted on the ABY and the numbering was changed accordingly. 

Still confused - The figure on the left shows the fuse numbering on the 3B and the figure on the right shows it for the ABY (and ADU).

By the way - Fuse S22 is only used on diesel engined varieties of the Audi 80/90 series... And while we are talking about fuses, many S2 owners will have noticed the little red two-fuse-carrier labeled 'Motronic' that resides in the fusebox. On the 3B, this couples fuses S26 and S27 (for the lambda sensor heater and ECU) whilst on the ABY, it couples fuses S27 and S28 (for the ECU, fuel injectors and MAF). Now where's the sense in that ? 

Click here for more details on the S2 Motronic schematics.

Last Updated 8th April 2002