Renewing the gear selectior on a 2002 CL500. With the wiring harness connected (8 pin plug), the old selector unit always made a subtle "Click" when the ignition was on and the brake pedal was depressed.

In testing the replacement unit prior to installation, with the harness connected, power on, and brake pedal depressed, there is no clicking noise. And the selector cannot be moved out of park.

Is this a defective unit or does something else need to be done to permit the unit to shift out of park?

Thanks.