Reading Electrical Connector Diagrams & Pin Numbering

[Legacy777]

This post was from another post, but I think it's important enough to make it's own thread for referencing how to read the electrical diagrams, specifically the pin numbering on the electrical connectors.


Take a look at these two diagrams, specifically the numbering for the B46 connector

http://www.main.experiencetherave.com/s ... _page1.jpg
http://www.surrealmirage.com/subaru/fil ... ntrol2.jpg

The numbering for the B46 connector when looking at the TCU I/O is oriented as if you are looking directly at the TCU connector. The number 1 pin is located in the top right corner, and looks something like this:

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10 09 08 07 06 05 04 03 02 01
20 19 18 17 16 15 14 13 12 11

Now when you look at the diagram that shows the B46 connector from the chassis side wiring the numbering is flipped and is listed like below:

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01 02 03 04 05 06 07 08 09 10
11 12 13 14 15 16 17 18 19 20

If you can picture it in your head when you put the TCU connector and the chassis connector together the numbering matches up. So as you can see, depending on what diagram you are looking at and how it has the number orientation laid out, that can make a difference on how you read which pin number is which. This scan from the fsm also shows what I'm talking about.

http://www.main.experiencetherave.com/s ... ectors.pdf

Another good way of verifying you have the correct pin to make sure the wire color matches what's in the diagram. Hopefully this will be helpful for those of you that are just getting into reading electrical diagrams.