what is it for?

[jiminEcricket]

hello, i have a grey market 1989 525i. i need to replace my turn signal switch. i have found one at the local salvage yard, but it has BC on the switch where you can push it inwards to activate "something" . my car does not have BC on the switch and cannot be pushed in. my car is wired for many options that it does not have,but i may still try this used switch if it is for an option that i deem worth it.

[gmannino]

BC is the computer on the dash, it toggles between the different view options on the computer readout.

[Airborne001]

Allows you to ship data from the OBC up to you dash for closer monitoring.

[Toomas]

You need the "large"* OBC unit to use the switch.

*- bunch of buttons near the radio where you can check outside temp, fuel consumption, range, time and date and maybe something else.

[jiminEcricket]

i got ya. i dont have the upgraded obc sooo. i guess i'll buy the switch since it is only $5 and put it in (possibly the obc from the donor car also). thanks for the info