Golf 3 TDI Wiring Harness Repair - Diagnostic Aids, Schematics

Hi.

I'm staying with my sister for the weekend, and she drives a Volkswagen Golf 3 1Z TDI with 90 horsepower, manufactured in 1994, without air conditioning or a water-cooled turbocharger (WFS).

A few days ago, when I tried to start the car, there was some smoke coming from the wiring harness in the front. The car didn't start. Since then, it hasn't started at all.
Freie Werkstatt war schon dran, hat im Kabelbaum ein verschmortes Kabel ausgetauchst, fand aber keine weiteren Fehler. Ich hab ein baugleiches Steuergerät dabei, und einen Kabelbaum (da fehlt allerdings ein Stecker zur ZE hin...). Steuergerät tauschen bringt nichts. In der Werkstatt sprang er mal kurz an und lief im Leerlauf, nachdem wir 12 Volt direkt aufs Elab gelegt haben. Aus dem Steuergerät kommen dort keine 12 Volt raus... G"It was not possible to proceed."

"Unable to read the control unit; no connection can be established with the control unit. This is true for both VAG-Com and a Bosch diagnostic tool in the workshop. Other control units, such as the ABS module, can be easily accessed and read."
Relay 109 activates when the ignition is turned on. However, there are only 4V present at the pins of the relay base after the relay has been activated...
We therefore suspect there is more burnt material in the wiring harness. Furthermore, we need to find the faulty component that caused the cable to melt.

Here are the questions: How complex is the wiring harness installation? Does anyone have a complete wiring diagram for a 1994 Golf 3 TDI without WFS? Does anyone have the pinout for the engine control unit connector? Does anyone have the pinout for the fuel pump connector? What resistance values should the solenoid valves for the EGR and turbocharger control have?

Thank you in advance for your input. I should be able to manage it tomorrow, but unfortunately, my sister lives about 250 km away and needs her car .

Best regards, Matze.