VW Lupo Won't Start: Dead Starter Solenoid Circuit Fix

Having dealt with a similar starting issue on my 2003 VW Polo, I have some relevant experience to share. The symptoms you describe match what I encountered, no starting, complete power loss to the starter system. After checking the fuse box thoroughly, my mechanic traced it to a damaged wiring harness near the steering column where the ignition connects. In my case, corrosion had caused a voltage drop in the circuit, preventing proper power supply to the starter solenoid. The repair involved: Complete diagnostic scan, Testing all fuse box connections, Replacing a section of the wiring harness, Verifying proper voltage at key points Total repair cost was 95€ including parts and labor. To provide more specific guidance for your Lupo, could you share: Has the check engine light been on? Did this issue start suddenly or develop gradually? Have you noticed any other electrical issues lately? Was the battery tested? Knowing these details would help determine if your issue matches the circuit break I experienced or points to a different electrical problem.

Thanks for the helpful replies. I had my last service at 71000km and have since noticed some intermittent electrical issues. The battery terminals were cleaned and tested fine during service. Regarding the questions: Check engine light comes on briefly then goes off, Issue started gradually over 2 weeks, Dashboard lights flicker occasionally, Battery tested good at 12.6V The voltage drop seems consistent with what others experienced. After testing the ignition switch again today, I noticed the connector feels loose. Could this be causing the circuit break that prevents starting?

Thanks for those additional details about your Lupo. The symptoms you describe, particularly the loose ignition switch connector, strongly align with what I found on my Polo. The intermittent electrical issues and flickering dashboard lights are classic signs of a failing ignition switch or compromised circuit. When my Polo had similar symptoms, the loose connector was indeed causing a circuit break that prevented proper voltage reaching the starter solenoid. Based on your voltage reading of 12.6V and the gradually developing issues, this points to a connection problem rather than a component failure. The ignition switch connector likely needs either: Reseating and securing properly, Cleaning of corroded terminals, Complete replacement if pins are damaged The repair on my car cost around 150€ for a new ignition switch assembly. However, if just the connector needs attention, costs should be much lower. Before replacing parts, have the voltage drop tested specifically at the ignition switch while attempting to start. This will confirm if the loose connector is causing the car won't start condition.

Thanks for the input. The voltage drop testing at the ignition switch gave me the answer I needed. After removing the steering column cover, I found significant corrosion on the ignition switch connector pins, which explained the intermittent power supply issues. My mechanic confirmed the circuit break was caused by this corroded connection preventing proper voltage from reaching the starter solenoid. The repair involved cleaning the connector pins and installing a new wiring harness section, since some wires showed damage from the corrosion. Total repair cost was 120€, mostly labor for accessing and replacing the wiring. The car now starts perfectly and all electrical issues are resolved. This matches what others experienced with similar symptoms. For anyone searching with the same problem, checking the ignition switch connections should be one of the first diagnostic steps when dealing with no-start conditions and electrical gremlins. Will mark this thread as solved since the relay switch and power supply issues were successfully addressed. Thanks again for helping diagnose the root cause.