I was recently working on a project that involved using a combination switch assembly used “normally” in the cars for Indicating Directions, Wipers, Headlights and Horns! For those who work on such projects which involves using things which are made for something else to do things that they usually dont do..this might be the post that can get u going and you can Decipher the full console/part in about 10-15 minutes.

Usually the generic way is to check each and every connection using a DMM as a continuity tester and figure out which switch closes which connection..which is very lengthy and often makes one impatient.

Here are a few tips/steps/way outs/notes/whatever:

  1. Open the console(only the outer covering) to see where the wires land up. Never ever open a switch assembly because it might contain some springs or mechanical arrangement that might be difficult to re-assemble.

Rear Assembly “Almost Exploded”

Front Exploded View

2. In many of these Assemblies the switches for a common purpose are base colored the same while to distinguish between them line colors are given. Like in the photo below the green wires are for Indicators wherein the all green wire is Common, the Green-Red               ( Syntax: Base Color-Line Color) is the Left indicator and Green-Yellow is the right indicator. Once you find wires of common base colors ..probe one without any line color to ones with a line color but same base color. and do some mechanical movements..a beep will show the contact made..then carefully document it in a diary/notebook.

Wire Harness Connector

3.When you have still some connections left to decipher ..Follow the following algo:

  • Initiate a mechanical switch and analyse the movement..because it is obvious that somewhere in the world in your hands a contact is being made..it might be that some copper strips be making contact when a plastic bar presses the strip..or a metallic piece moving on a PCB pad.
  • Once you figure where the action takes place..probe the point and There you get the missing links.
  • Now if there are some more wires left..lets follow the principal of exclusion and work backwards..trace the wires back to the point of contact and see what sort of mechanical action produces that kind of a reaction.

PCB Pads and the copper strip for Wiper control and the Green-Red Wire of the Indicator System

Copper Strips and the black contactor that makes and breaks!

Hope you like the post and manage to decipher a few assemblies. Keep me posted on how this helped.

Happy Tinkering!


One thought on “Deciphering almost any Automotive Combination Switch Assembly

  1. Never open an assembly unless:
    A. It’s a non-spring and ball type.
    B. You are an expert at common mounting techniques and mechanical switches
    C. You have spare that you can sacrificeto learn.
    I learnt my lesson with a swift kick on my arse.

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