Remote Control Door Lock Receiver (RCDLR)
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The RCDLR is a multi-function module which controls all the vehicles antennas for passive and active keyless entry, as well as vehicle theft deterrent and vehicle starting. The RCDLR will send an AC voltage signal and provide ground to the passive antennas. This will enable the antennas to send out the low frequency broadcast challenge to a keyless entry transmitter within range.