gusgus,
If the work was done by a Chevrolet mechanic, perhaps he just disabled the PKE system instead of disconnecting it. Turn the ignition to ON and determine if the PASSIVE KEYLESS ENTRY lamp illuminates. If it does not perhaps that is what he did. Perform the following to enable it.
Passive Unlock/Lock Disable Procedure
The Passive Unlock/Lock Disable Procedure allows the operator to turn “OFF” the passive functions of the PKE system. The function can only be accessed from the transmitter in range/key not in ignition state. The following conditions must occur:
Valid Transmitter is in range.
The key is not in the ignition.
The “DOOR” button has been pushed for longer than two seconds.
When these conditions are met, the PKE module will lock the doors and will then unlock the door(s) to notify the operator that the command has been received. Also, when the passive feature has been disabled, the “PASSIVE KEYLESS ENTRY” lamp will not illuminate for bulb check when the key is first turned “ON”. When the passive feature has been disabled, repeating the procedure above will enable the passive unlock/lock function and the “PASSIVE KEYLESS ENTRY” lamp will illuminate upon ignition “ON”.
Hope this helps.