Alanjenna

Hi All Just taken a DNS500 Sat Nav out of a Honda and put into a Lexus. It was quite a job but managed to do it. Can anyone answer some simple questions. 1) Does the speedometer feed wire need to be connected. 2) Does the reversing wire need to be connected. When using the Sat Nav all is well until I turn it off, the unit says its off but the voice still keeps coming out of the speakers over the radio, any ideas. Many thanks. Alan