1990 535i One-button Alarm Remote

[brendanm]

I've got a damaged BMW Alarm remote, it's a one-button remote with a broken corner where the key ring attaches. I want to replace the case, or implant the guts into a new case. However they seem difficult to find.

Part No. 88 88 1 600 205
FCC ID: A269ZUA087

I've found lots of 3-button remotes, same shape and size, same FCC ID, but with 3-buttons. Bavarian Autoparts said that it can't be used in place of a one-button. Is that true?

I've also found a few one-button remotes, but they want $120 US for it. Has anyone got any suggestions, or been through this process before. What kind of options are there?