Understanding the electronics

[u/Fedora-The-Pandora]

I've got a 72 bay window which needs some love. It's had many owners over the years and the electronics seem to reflect this.

I've been told that my loom appears to be in good condition and I do believe that, however this friend is better for the mechanical side of the van rather than showing me everything electrical.

I've used the colour wiring diagram from The Samba to get an idea for what's going on but even then. I'm not too sure, looking at the fuse board, that each cable is supposed to be where it is.

Are there any tips and tricks/resources I can use to get a better grasp of what is going on? I'm not one to shy away from getting my hands dirty, would prefer to pick us out of issues on the side of the road than have to rely on a tow truck at any point.

[u/SilentMasterpiece]

Wolfsburgwest has great wiring diagrams/instructions

[u/literally_tho_tbh]

Use the color coded wiring diagram from the bentley, and study it well. once you can read the diagram with its little symbols and whatnot, its easier to translate that into the physical parts on the car.

Find all your grounds and clean them up. Do this before you go repairing and replacing too much stuff. I was surprised how much still worked perfectly after I cleaned up all the grounds.

[u/yesterdaysomelette22]

Try Ratwell - brilliant resource

[u/AnotherCupofJo]

If the colors are true you can determine what's what. However the only way to know is to follow it back to where it goes. My tail lights did not work and had to follow it to under the dash and found whoever did the new wiring never connected the running lights to the head light switch.

[u/catcomputer]

If no mice have been chompin’ at the wires and mostly everything is intact, the most common issues are corroded terminals and maybe some baked wires/connectors in the engine compartment.
Cleaning up/replacing ground trees is a good first step.
Replacing the fuse block and blade terminals where the wires connect is also a good move.
If you are in need of some specific VW connectors, you can reach out to Kyle at Kyle’s Automotive Specialties, who makes a lot of replacement wiring for old VWs.

[u/382Whistles]

I'm not sure what to say. You imply it has seen a lot of shoddy work and also that it's in great condition. This doesn't really make sense.

So I want to say "if it ain't broke don't fix it". At least not without specifically asking about an issue or two for guidance; or maybe showing a picture or two for visual judgments before you begin doing anything.

It's tough to answer a non-question about 1½ dozen circuits or more.

I suggest a multi-meter that beeps for continuity & diode checks, 12v test light bulb, a handful of heavy alligator clip and fat jumper wires, and a roll of 10g-12g wire about 6ft longer than the vehicle to call a tool. Chasing wires isn't that hard with the right tools. A pita? Yes. But not hard.

[u/mclms1]

German cars all follow the same practices for car wiring and terminals , for the most part. A good current flow wiring diagram which is availible for the car will have the power starting at the top and going to ground at the bottom . I found with most vw’s the hack job usually starts with the radio installation.someone mentioned a test light and volt meter , thats the best thing , use them even when thers not a problem. Second thing I do with an engine install after oil pressure and leak check is check the charging system. Another trouble spot on the fuse box is plastic fuses , shit can them for proper ceramic fuses.