I just replaced the antenna base yesterday, and much to my surprise, under the headliner, I discovered a mysterious electronic box which is located about 3” away from the base bolt hole in the middle.
Does anyone have any idea what this might be? I used a YouTube video to walk me through the R&R of the base, and the guy’s LT1 didn’t have this (I also have an LT1).

 

That is the RCDLR. The receiver for the fob and TPMS. 2006 and 2007 have it mounted behind the driver side rear seat.

 

thank you! 🔑

 

You have a 1LT

 

If it doesn't have a Remote Control Door Lock Receiver (RCDLR) it doesn't have remote control door locks?

 

That feature was standard equipment on all models/ all years of HHRs.

 

That is why I included the part about 2006-2007 having it mounted in a different location. They did not have TPMS a standard equipment.

 

Good info! So this mystery box houses both the TPMS Receiver and RCDLR, if I’m getting this all in piecemeal by different sentences posted. That’s what I really wanted to know. Got it!

 

It was all in one sentence in post #2. The module is RCDLR; it receives both TPMS and fob signals.