Most likely it’s the connection to the switch itself, they seem to have a poor connection there and the connection arcs and burns away the metal in the switch unit. It needs repairing, sometimes a piece of wiring loom and connector are required and sometimes the central console unit will also need to be replaced
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Smart Car Specialist
Unit 10
Foundation Units
Westfield Road
Slyfield
Guildford
Surrey
GU1 1SF