Terraza No-Start: Bad Ignition Switch Diagnosis Guide

I had a similar issue with my 2003 Buick Rendezvous last winter. Having moderate experience with electrical issues, I first thought it was just a starter solenoid problem, but it turned out to be more complex. The symptoms were identical, engine would crank but not fire up, and voltage readings were all over the place. After checking the fuse box thoroughly, I found the real culprit was a damaged wiring connection to the ignition circuit. The insulation had worn through, causing intermittent power supply issues. The repair involved replacing several corroded connector pins and a relay switch that had failed due to the inconsistent power flow. Total repair cost was 95 Euro, which included diagnostic time and parts replacement. To better assist with your specific case, could you share: Have you checked all fuses related to the ignition system? What are the specific error codes stored? Is there any pattern to when the problem occurs (cold starts, wet weather)? Have you noticed any other electrical issues before this started? Once you share these details, I can provide more targeted suggestions based on what worked in my situation.

Last service done at 117302 KM. After reading your advice, I checked further and found significant voltage drop across multiple circuits. The wiring harness behind the steering column shows visible wear, which could explain the intermittent power issues. The stored codes mainly point to circuit breaks in the ignition system. The problem seems most noticeable during cold starts. I managed to test the voltage at different points and found irregular readings at the relay switch connections. Before tackling a full replacement, would it make sense to first inspect the connectors for corrosion?

Your approach to checking the voltage drops is spot on, I had almost identical symptoms in my Rendezvous. Before jumping into a full wiring harness replacement, inspecting and cleaning the connectors definitely makes sense as a first step. When my car would not start, particularly during cold mornings, cleaning the corroded relay switch connections provided temporary relief. However, the underlying issue was the damaged wiring insulation causing intermittent circuit breaks. The voltage inconsistencies you found across multiple circuits strongly suggest a similar root cause. The location of wear behind the steering column matches exactly where I found my issue. One thing to watch for: check if the power supply to the ignition module fluctuates when you wiggle the wiring harness. In my case, this test clearly showed where the circuit break was occurring. A few checks worth doing before any parts replacement: Clean all ground connections, Test the fuse box terminals for loose connections, Verify the relay switch is clicking when powered Given the similar age of our vehicles and matching symptoms, you might save time by focusing on the wiring harness section where visible wear is present, rather than replacing individual components first.

Thanks for the detailed response. After following your suggestion about checking the wiring harness movement, I definitely notice power fluctuations when wiggling the cables. I cleaned all the ground connections and inspected the fuse box terminals as recommended. The relay switch does click, but the sound seems weaker than normal. Your experience with the similar issue in your vehicle has been really helpful. Based on the voltage drop patterns and visible wear spots, I think Ill start by replacing the damaged section of the wiring harness rather than just cleaning the connections. The circuit breaks seem too severe for a simple connector cleaning to fix permanently. One question before I order parts, did you need any special tools for accessing the wiring behind the steering column? The repair manual isnt very clear about the removal process for accessing that area. Also wondering if I should replace the relay switch while Im in there, given the weak clicking sound.