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Old 06-30-2010, 07:25 AM   #18
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Join Date: Nov 2009
Location: Whitby, Ontario
Posts: 669
My Ride: 2009 335Xi Sedan
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what ends up happening is the collector is pulled to 0.7 vdc when I close the switch (selector lever) and ground base; its Collector voltage is 5vdc when transistor off (emitter @ 0 vdc). The emitter voltage matchs the collector voltage @ 0.7vdc (which is not enough to power the LED; testing has shown I need about 4.5vdc to get LEDs to light). How can I pull-up the collector voltage to 5vdc..... I'm missing something basic. tried resistor in series on base signal; no effect..... Now I know why I took my degree and went into IT..... all 1s and 0s.... LOL I'm still designing digital circuits, it the analog crap thats got me stumped.

Also, since you obviously know what you're saying, I could go with your previous suggestion in regards to isolating selector switch and applying power to it, but how whould you handles the M/S signal coming from TCU? X1600 is a 3pin connector and pin 2 seems to control M/S LED, however pins 1+3 seem to go through the lighting panel and pass through a diode. not sure if I can just jumper pins 1+3 using a diode, or plain jumper wire. If I'm to eliminate the PRND circuit brd, then I'd have to address that signal..... Tomorrow is Stat holiday in Canada, guess I'm going to have to test on my car and find out.
My Rides:
2009 335i Xdrive

2000 Z3M Roadster

Last edited by Nachos23; 06-30-2010 at 07:38 AM.
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