Hi All,
I am working on installing emergency warning lights into my 2017 F250 and need to have some lights turn off when I am in park. Ford does provide a wire that goes to ground when in park but it needs to be pulled up to VPWR by the 10K Ohm pull up resistor. Now I will admit I am not the best when it comes to this stuff so Im not 100% sure how to do this. I do plan to have the ground activate a relay to change it to 12V.
Here is the description and wiring diagram that Ford gives:
"PCM Pin 6.8L C1551E-19 Circuit No. CET22 Wire Color: Gray/Brown • An output from the PCM that indicates when the Transmission Range Sensor is indicating that the Transmission is in the Park Position. The Low Side driver in the PCM will pull this output to ground when active (Transmission is in the PARK Position). To properly reference this output, the customer supplied external controller/device needs to pull this output up to VPWR with a 10K Ohm resistor. Thus when the output is active, the voltage at this output will be 0 volts. When this output is not active, the output will be pulled up to VPWR by the 10K Ohm pull up resistor."
Any help on this would be much appreciated. I don't want to turn this into an expensive mistake!
What stops You from installing the stuff indicated in the wiring diagram?
What stops me is that I dont 100% understand what it is I need to install. From with I understand they want a 10K Ohm resistor to go from the wire to 12V? wouldn't that cause a short? Would that wire still be negative switched? Like I said Im very new to this and my knowledge is limited to with I have looked up and learned on my own. Last thing I want to do is fry the PCM on my truck. lol
10 KOhm will not short circuit anything in the vehicle. What You need is to understand how the system works.
It's too late during the day for me. Let's wait for fresh ideas.
I believe that the LSD -- low side driver -- is what's known as an open-drain or open-collector switch. This means that you could connect that lead directly to the Arduino and use an INPUT_PULLUP input mode on the pin; you wouldn't need to connect it to 12V and then translate that back down to 5V.
Because it's an automotive environment you might want to add a series resistor and a cap to GND (e.g. 1K series resistor, 0.1uF to GND) and perhaps a transient voltage suppressor (TVS) diode to snub any static or voltage transients that may appear on the line.
One alternative is to visit a garage having knowledge needed. F250 sounds like a car.
