While I have never worked in the automotive market, I have worked with schematics my whole life. I do find the Ford Diagrams and methods to be a little confusing. It appears to me that according to the diagrams that you are on the correct line. I guess I would check the back up lights and start working back from there.
I don't see an issue with tapping on the return (ground) side of the bulb, other then if the bulb was out you would also loose your trigger. (this could be considered a good thing) Yes, you would see some voltage drop on the ground side of the bulb, but I would not expect it to be high enough to cause the trigger to not work.
The C3136 connector should have the correct line. For my year(2004) its says pin 9. The C3136 connector pin-out is alternating from side to side (odd side and even side) unlike some of the other connectors that are serial.
Good hunting
-greg
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-greg
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"Goldilocks" 2020 Ford Transit High Roof Extended 3.5 EcoBoost AWD Homebuilt
When time permits I'll be digging into C3136 to make sure the Ford schematics bear out what I actually have. I did learn a lesson which is check connectors first before following the published schematics.
Chances are good my lack of +12 VDC in the black/pink wire is because that particular wire is not connected according to the schematic.
Linear Mode
