Hey all,

Own a 2004 Audi a4 B6 1.8T., Quattro. One day, came to try to start it. Turning the key in ACC, everything functions normally. Lights, radio, wipers, etc. work fine. Turn key to start engine, and absolutely nothing. No noise at all. No turnover.
My battery, starter and alternator all work fine. I know this because I have tested them, and I can bypass the ignition starter wire, by connecting the battery to the starter solenoid and the car starts right up! Runs fine. I can drive it and no issues at all. But once I turn engine off via key, have to bypass ignition again to restart.

I'm thinking ignition switch? All my fuses are good. I replaced a few relays in the ECU box, but no change. How can I test my ignition switch with a multimeter? Any other tests someone recommends? I like to know the exact problem and save money, instead of replacing many parts until issue is fixed...

Appreciate anyone's help!