Where does the ground come from?

So, been going through the 53 year old wiring harness of a 70 GS. There were a few snips and couple connections I had to fix but not bad.... I see in the wiring diagram, the main dash harness has a black ground wire for the cigarette lighter, wiper switch, light switch, gauge cluster, clock ground, in the plug for the speedo, and the ground for the heater control light sockets. I didn't see it on the wiring diagram but there is also a ground wire to the main brake pedal assembly.

Question is... Where does the ground initiate and come into the harness?

I know the ground wire from the battery goes to the engine, then there is a ground strap from the engine to the firewall. But how does the ground get from the firewall to the black wires in the under dash harness?

I ask because if the ground is coming through into the harness from the brake pedal assembly since that is bolted to the firewall, I am hoping I won't have an issue since the brake pedal assembly was powder coated....

 

The car's components that make up the frame, body panels, (fenders, body, hood, deck (trunk) lid, floor pans etc. Anything that is connected to them is the "ground", the negative battery post is connected to them, the engine is connected to them. All of the car's "energized" components (everything that needs power) is provided through wiring and and the "ground" is accomplished through switching. (connection completed) .

If you need or want to discuss any/all of this, PM me and I will make time to talk on the phone and help you understand.

It is not complicated (difficult) to understand, but it is complex (many things to grasp at the the same time).

Once you get the basic theory and understanding, you can "see" and realize how to navigate and fix things, or decide you want to let someone else tackle the problems.

PM me, and I will set time to talk on the phone.

It only costs your time, not a penny more...

 

Thanks. PM sent.

 

In simple terms you can ground to any metal panel of the car.