323001800 - N001 CIGAR LIGHTER/CURRENT SOCKET NOT WORKING

When the buttons on the front panel of the radio are pressed / operated, the corresponding functions are selected. When the controls on the steering wheel are operated, however, the corresponding function is not selected.
TEST RESULTS
1CIGAR LIGHTER CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the cigar lighter/current socket and, in particular, make sure that the internal thermal protection device has not intervened as the result of overloading.Move on to Step 2Thermal protection intervenedReplace the cigar lighter/current socket.
2CIGAR LIGHTER ELECTRICAL CIRCUIT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the following, in order:- Cigar lighter fuse- Cigar lighter relay- Cigar lighter power supply and earth- Continuity and insulation of cigar lighter electrical circuitEnd of diagnosis1.Component defective2.Connections not correct1.Replace the component (in the case of a fuse, find out what caused it to blow)2. Restore the correct connections    See E3070 CIGAR LIGHTER / CURRENT SOCKET