One problem related to wiring has been reported for the 1999 Volkswagen Golf. The most recently reported issues are listed below.
Instrument cluster fire in 1999 vw Golf tdi: 2003-01-14, mileage 88290, lights and gauges on instrument cluster were acting flaky and not working properly. Some lights were dim and some were burnt out. 2003-02-05, I bought new instrument cluster. Plan was to have dealership replace faulty one with new one on 2003-02-10. A few days after I bought new one, the car’s existing one suddenly emitted sparks while I was driving in a snow storm, and caught on fire! thick, acrid smoke billowed from underneath the dashboard, forcing me out of the car. I put out the fire with my jacket and some snow. 2003-02-10, dealership replaced instrument cluster. During the first heavy snowfall after that, car started bucking at low rpms and when attempting to shift gears. Speedometer started fluctuating wildly, showing me going anywhere from 0 to 120 mph. Temperature gauge started fluctuating between 0 and danger zone, and temperature alarm sounded whenever the gauge jumped into the danger zone. Fuel gauge dropped to empty. Odometer froze up. 2003-04-04, mileage 90906, technician at dealership found 300 kilo-ohm resistance in wiring harness grounds. The four main ground wire ends were horribly corroded. As a result, there was no power going to the engine coolant temperature sensor, vehicle speed sensor, or coolant bottle sensor. Technician left the existing wiring harness in place, since most of the harness wires were working fine. He disconnected and capped the ends of the four corroded wires. He then ran new wires to the affected sensors (creating an “overlay harness”), crimped new connectors on the ends, and used heat shrink on the crimps. I haven't had any instrument cluster fires since then; however, I have replaced the ect sensor 7 times during the 15 years I have owned this car, possibly because of lingering grounding issues. Current mileage is about 392,000.