Review on Enhance Your BMW Key Experience: HelloAuto Key Replacement Button Pad & Smart Remote Cover for BMW 318i, 323i, 525i, 528i, 530i, 535i, 540i, 735i, 740i, 740iL, Z3 by James Holker

The buttons on my original remote only worked about 25% of the time so I had to manually unlock it with the key. I thought it was a signal problem so I changed the battery. Bad luck. I came across this by accident while looking for another part for my car and decided to give it a try. I think the rubber inside was worn out so the internal switch wasn't fully depressed. The red area had to be cut off for the transponder chip, but now my key works 100%! Make sure you leave the "old" red part in place.