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Old 06-27-2010, 08:01 PM   #15
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Join Date: Nov 2009
Location: Whitby, Ontario
Posts: 669
My Ride: 2009 335Xi Sedan
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Originally Posted by Arty View Post
In that case, if you are ditching the E46 LEDs {and if they are not used for the dash} you can simplify.

Actually, before I ohm'd out the circuit, that was what I was hoping to accomplish, however, the M/S LED is also open ground and comes from connector X1600 (white one) see schematic above. Goes from transmission control unit to steptronic switch through lighting circuit board. It's that signal that has me thinking I need the interface board.... But could use a single transistor for just M/S LED if your suggestion for shift selector works. Need to verify how the switch is located/functions... ie completely isolated as shown in schematic, or does it connect to chassis ground where mounted? Need to verify visually and electrically. If it's isolated, maybe I can use your suggestion for selector switch and use single PNP transistor to power M/S LED...... Pouring out there tonight, and RFP due Tuesday night, so probably will check Wed night and report with hopefully a functional shifter.....

Originally Posted by profor View Post
Check if LEDs are not fed by PWM voltage. You mentioned around 6V which is not normal in car and this reading YOu can get with normal multimeter and PWM signal.
Well, accoridng to the current e46 schematic its fed by 15vdc. What I can't find on ANY schematic is the ton of additional circuitry that exists on the current lighting circuit board, that include, coils, caps, diodes (in addition to LEDs), etc..... They must drop voltage down. Also, on the current design, there is both CanH (15vdc) and dimmer voltage being fed into board. New DCT shifter has only 1 connection for Ambient lighting on shifter plate and it must be connected to dimmer voltage..... There is no ambient lighting being fed to DCT shifter when headlights/running lights off. Only illumination during day is green PRND M/S LEDs..... They do not seem to be impacted by ambient lighting circuit (separate powers; common ground).....
My Rides:
2009 335i Xdrive

2000 Z3M Roadster

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