E30 Wiring Diagram Basics

[DaveSmed]

You'll find that under "Power Distribution"

[RobertC]

Dave,

What a awesome post. I do well with electrical myself and am quite familiar with the diagrams. I have to say, you presented all of that information in a wonderfully well written tutorial.

I know alot of DIY's get hung up on electrical, even if they do have the ETM it sometimes can still make no sense to them.

Your detailed tutorial is some of the best reading I have seen on a forum board in a long time.

Huge props for the contribution. (actually I think the post needs to be stickied for future reference, its actually a huge technical contribution)

:up:

[xworks]

Fantastic thread, very well written.

[keflaman]

A very well written tutorial. I have a question regarding the cruise control schematic (6571-0) for the 1987 3 series. Immediately under #6 fuse it says "See Fuse Details" and slightly lower and to the left of splice 241 the wire ends in an arrow and says "Fuse Details".

Is that the same as the "Fuse Data Chart" on page "0670-1"?

[DaveSmed]

Good catch, both that little gap in between the fuse and the splice, and the gaps in between the splice and the triangle in the violet/white wire mean you are not seeing the entire circuit, only a relevant portion to the cruise control.

Check out 0670-10 for the fuse details (Located in power distribution)

[keflaman]

Wow. You have no idea how much clearer I can now see what's happening in those schematics. I am adding CC, OBC, lighted mirror, and heated seats to my '91 318is and I'm trying to stay true to the ETM so any problems down the road will be easier to troubleshoot.

Thanks!

[NLM Hollywood]

Any chance you have a pic of this G200 ground point? My 86 es has electrical gremlins and I keep trying to track them all down. I've always wondered what this ground was (can't get the good pic to work, black wire with rusty screw of this one).



Clearly not G200 if it's a star ground point for multiple circuits.

[Quadrajet]

Dave excellent info! While I didn't need this info myself, having been working with schematics for years(unfortunately), I'm sure it makes clearer what's up. Now when I'm passing info to folks I'll tell them to look this up.

Also you are one of the reasons I'm still into E30's. Your sage advice helped me resolve a couple issues I had with my first E30.

[DaveSmed]

Any chance you have a pic of this G200 ground point? My 86 es has electrical gremlins and I keep trying to track them all down. I've always wondered what this ground was (can't get the good pic to work, black wire with rusty screw of this one).



Clearly not G200 if it's a star ground point for multiple circuits.

Your rusty screw is for something aftermarket, and is probably nothing to worry about.

G200... no picture, but if you remove the knee bolster, lay with your back on the door sill, and look up with your head by the brake pedal, you should see it.

[DaveSmed]

Dave excellent info! While I didn't need this info myself, having been working with schematics for years(unfortunately), I'm sure it makes clearer what's up. Now when I'm passing info to folks I'll tell them to look this up.

Also you are one of the reasons I'm still into E30's. Your sage advice helped me resolve a couple issues I had with my first E30.

Glad to hear it getting passed around! A basic understanding of schematics is pretty much mandatory for the DIYer, and yet many people have trouble grasping all of the info contained within.

Also happy to hear my two cents has helped ya out in the past with your car.

[Unearth078]

i think i know why you picked this circuit... the unloader / starter wiring issue? i have to trace down a few gremlins in this awII sedan. got the interior all squared away and clean to figure out my blower motor and windows dont work lol. the catch? blower is intermittent so i believe the starter wiring is correct..

[limas]

Thank you so much for this tutorial. I have a question regards to the window breaker switch. Initially, i have to inform you all that my 2-door E30 is a 1984 model M10, swapped to M42. I bought as M42. So, i am trying to solve some problems on my own. To the point, i pushed out the window breaker switch, as i did not know what is this part. I "google" the part number and i found the answer. Behind the switch, there are 2 green-blue wires, as refered to the first post of this thread. I suppose each one is for each window.


p.s.: I used a multimeter to check the circuit and the functionality of the window breaker. When the button is pressed, there is circuit and the multimeter sound a "beep". On the other hand, when the button is not pressed, there is no circuit and the multimeter does not sound a "beep". So, i conclude that the window breaker switch is functional.

Please, correct me if i am wrong.

Regards,
Mike

[limas]

Hi, according to the last post, i capture some photos to see you exactly the wiring connection.

On the first attached photo, yo can see 2 gray-green wires. These 2 wires are connected on the window breaker switch.

The second photo shows the wiring behind the driver's window control switch. I checked the circuit between the left wire of the first photo and the #3 pin (to the point the screwdriver points) on the driver's side. I hear the "beeeep", so there is no wring cut.

The third photo shows the wiring behind the passenger's window control switch. I checked the circuit between the left wire of the first photo and the #3 pin (to the point the screwdriver points) on the passenger's side. I hear the "beeeep", so there is no wring cut.

In addition, there is a circuit between the #3 pin at the driver's side and the #3 pin at the passenger's side.

What is the spare gray-green wire (the right one) used for? My windows are free to be used, even though the window breaker switch is pressed or not.

Thank you in advance.

[limas]

I tried to replace the K5 relay with K7 but the problem still remains.

I get 11.7V both on the green-gray wire behind windows breaker switch and on green-gray wires on the harness back from the window control switches.

I think i should not get any DC voltage while the window breaker switched is removed.