I think spac1992 is on the right track. Seeings that it used to be a company car, that button could have been removed. Now that you've put the button back in and wired it up it should work.
Is the wire connector connected properly? Maybe the pins were dirty or a bit oxidised from being exposed for so long. Give the connection a spray with CRC contact cleaner and make sure its snapped together firmly. Failing that, I can't help any further.