I’ve had the car for about 6 months now and it wasn’t until I looked for ways to wire in a dash cam that I noticed this thing. Stuck next to my mirror is a plastic thing, approximately 2" x 1.5" x 1/2" thick, shaped like the bottom of an iron. Its wire disappears into the headliner. Definitely an after market item. Any ideas? TIA 
If you don’t mind a WAG, I’ll guess that it’s a transponder antenna; for, for example, using toll roads/bridges.
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Johnny, I’ll bet that’s it. With any luck I can use its wires for the cam. Thanks!
I’m going to go with an XM window antenna. The last person pulled out the XM radio and just cut the wire left the antenna up instead of spending all the time trying to get the wires out and then having to deal with the adhesive.
This is similar to how my last one looked, but XM has been around for a while and the units are made by a handful of manufacturers so there’s a bunch of different styles of antennas out there.
Can you look closer at it and see if anything is written on it. Look from the front (through the glass) as well. A picture would be helpful too.
You may be right. (I am certainly not an expert.) I searched for images of XM antennas, and I do see some that are ‘iron-shaped’. Ever FastPass-type transponder I’ve see has been square. As I said, ‘WAG.’
Ok, I’ve figured it out, and boy are my ears red:o I went out to try to take some pics, then I wiggled it and realized it was held on with velcro. I peeled it off, unplugged it, and as I turned to go back inside to take some better pics, to my dismay my fob wouldn’t lock the door behind me. Then I realized that it’s the receiver for the remote start I had installed just a couple of months ago:smack:
I think that is a message from god or the universe to cut back on the booze or whatever. 
I don’t drink, and I can’t afford whatever.