S4 LH and EZK Connection Diagrams

[Zirconocene]

My winter project has been focused on making FoE harnesses and putting some thought and effort into how I'm going to make my replacement LH and EZK harness. As part of that work I find it helpful to go through and map out all the connections, so as to help myself visualize how I want to handle all the various interconnections and splices. I'm still working out the details on how I'll build my own harness but, in the mean time, I think that the background information is in a place where I can share it with some confidence in low errors.

This information comes from a partial disassembly of a harness from an '87, with supplemental information taken from the wiring diagrams. The wiring colors change from year to year, and the pin positioning in the ECU connectors changed (in the LH and EZK connector housings themselves, is what I mean), but as I understand things this general wiring diagram is relevant to US cars from '87 - whenever the GTSes ended ('94?).

Without further ado, here is the information:

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There's a lot of information there and it doesn't encompass the physical layout of the harness itself, but should be a good guide to helping understand what's going on with the connections to your ECUs.

Cheers

[blueline]

Even though the schematic is light years beyond anything I would know what to do with, I can tell that it is not only very professionally presented but that it also represents a lot of of detailed research, problem solving and diagramming. Nice! Thanks for sharing.

[dr bob]

Nice! I spent a few hours working on some of the wiring drawings, building them again in AutoCAD with highlighted layers based on circuit/system. Still a bit too complex for most owners with the jumps among pages. Bringing the actual wiring together in one panel is a very nice touch. And a bit of work for those playing along who might not know.

At this point, an owner could use three different diagramming methods for electricals. The early versions with vertical circuit 'rungs' focused on final elements is the best for troubleshooting on paper. The later style is a bit busy, and with all the links between sheets essentially demands that you try and draw the circuits in the early style. I printed out the panels and use a highlighter to follow along and keep track. The schedule and diagram you share here are essential to anyone actually fabricating (or diagnosing within) a physical harness.

Thanks!