So, further multi-meter led diagnosis has been done and I am now as sure as I can be that its the rotary connector. Today I have:
- Removed airbag unit, steering wheel and associated shrouds/trim
- Cleaned all contacts that were readily aaccessible
- Checked resistance to ECU from airbag plugs (results within 0.1 ohm of what the diagnostic computer states with airbag connected)
- Partial reassembly (left off shrouds)
So I can rule out the airbag as the issue on this basis. I have come back to the rotary connector as, looking at live resistance data while turning the wheel, resistance on the circuits seems to fluctuate between 2ohm and 5ohm, suggesting the fault lies there. I should have applied this test last time around, but I forgot that the data was live rather than a snapshot
.
A used replacement CIM has been ordered for £25 (new/refurbished ones are £250plus
). I will report further on progress.