We are having a problem I cannot find an answer to. We have the two original Key Fobs for my 2006 SLK 350. One of them works perfectly from a long distance to lock/unlock and open trunk...the other will only work when placing it near and aiming it at the IR sensor in the door handles (both drivers and passengers). Has anyone else had this problem? The only thing I can think of is that the RF (chip?) somehow went bad in the one that only works IR. Both start the car without issue and both will raise and lower the top, without fail, when placing them near and aiming them at the IR sensor in the door handle. Because this is my wife's daily drive and I rarely get a chance to get near it anymore I don't even remember if/when my key (the one that only works IR) actually worked from a distance, though I think it did years ago when I actually drove it sometimes.