Making an OBDII PCM to dongle adaptor cable | Page 3 | Ford Explorer Forums - Serious Explorations

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Making an OBDII PCM to dongle adaptor cable

@J_C It seems that I could power my VCM2 from pin #16 that way since it didn't come with a power supply. Thanks!

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@J_C I have a MIL, malfunction indicator lamp wire coming off of pin 2 wire #658 pink/lt green. If I were to attach it to a micro bulb do you think that the other tab/tang would go to the common ground?

^ Looks like that bulb along with others on the instrument panel, gets 12V through interior fuse panel, fuse 11, then the PCM grounds it to turn the bulb on. You can see it on this diagram attached below.


Slodering done except for MIL. I can't seem to get a good heat on the wiring connections enough to draw solder in completely on the bigger wires. I was unsuccessful attempting to solder to the mini-bulb tabs. It will work without it. I just thought it might be interesting to see what the light does or doesn't do during read/write.
dlcPCM bench adapter.jpg

I would just use a common 5mm encapsulated LED, with a hole in your project case just the right size to hold it (a tight fit), or they make tiny little LED holders but you don't really need them with the right sized hole in a plastic enclosure. Using a 12V supply, a 1K resistor in series to limit current to 10mA (depending on LED color but close enough to 10mA, within the limits of a 5mm/100mW LED anyway).

12V LED.png