Astra no Hooter CIM Module ?

[BQW]

Has any one repaired, what I understand is a common fault on Mk5 Astras with the horn button on the Steering Wheel not working.
I have not done any fault finding yet, but the CIM (Colombe information Module), I am told is the prime suspect ?
I am also informed there is a extra clip to fit before reassembling, Vauxhall part number 93196910 ?
Any one with experience of this fault ?

 

[cdbe]

I turned down the brightness of the dashboard lights to a just about acceptable level and the horn worked for another year or so till I sold it. Strange fault.