Convert Switched ground cicuit to common ground to power automotive LEDs

Discussion in 'The Projects Forum' started by nachos23, Jun 20, 2010.

  1. nachos23

    Thread Starter New Member

    Jun 20, 2010

    Looking to design a low power circuit to drive the LEDs in a new shifter I'm trying to retrofit onto my current car. Problem is, the current design uses a common power and switched ground design to complete the circuit and power the PRND and M/S LEDs. The new shifter pictured below (from a 2010 650Ci) uses a common ground, switched power design to power the PRND and M/S LEDs.

    See pics of project and schematic of current circuit below:


    Buddies car; gave me the idea; he never got it working....


    Schematics of current design in my car. Couldn't find schematic showing actual shifter LEDs. I believe they are attached to signal wire located just above transistor.


    I'm looking for a simple low power circuit to utilize the current ground switching through selector lever to trigger a gate, relay or other such device to output a signal to drive the PRND and M/S LEDs on the new shifter.... I'm an electrical engineer, 20 yrs removed from electronics design and unfamiliar with new technologies and devices available to me.

    Considering it's for a car, power, size and environemental tolerances are critical. Any suggestions? I was considering a traditional micro relay driving the LED through a resistor to drop the voltage.... Would need 5 duplicate circuits to run the 5 LEDs...... likely NOT the best solution...

    Thoughts, suggestions?