Followed directions above and 18 button works after a fashion. I do experience the following problems- after only 10-15 miles
a-Mph is approx 30% of speedo reading
b-brake lite failure warning but all lites function and are stock
C- range, mph and mpg do not work

My logic tells me that the speedo input functions but needs a setting changed.
The brake light warning is perplexing
Could I be not getting the info from the fuel gauge

will do more trouble shooting next weekend

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW On Board Computer Retrofit / Conversion

I'm not sure about the other issues, but the brake lamp warning circuit is a common question. The circuit in these cars is a dual-switch circuit (one for backup I suppose). So, if one half of the switch breaks, the lights will still operate, but it will give you a warning on the computer. Simply replaced the pedal switch, and the message should go away.

- Wayne