+100 to Subaru Wangara, especially Taylor the service desk girl
Visited her today asking for the stop light switch and told her what was going on. Rather than just giving me the new switch (for $27) she offered to get the boys out the back to plug in the diagnostic tool and confirmed for me it was a stop light fault. Took 5 mins, and I didn't even have time to finish my cup of tea!
Just got home now and fitted the new switch...been for a blat and no disco lights!
For anyone interested in the future, here's the details:
Instructions
Switch part number - SU-83311FJ000
New switch
Old switch before removal
You need to be a bit of a contortionist to get up under the dash to the switch, but it's easy to twist in and out once there. Took a few attempts to set it up perfectly, the thread on the shaft makes it jump slightly backward as you snap it in place, so you need to allow for that when setting it up. Or do it a few times like I did!