2017+ Super Duty F250 rear turn signal resistor install on OEM housing w/ BLISSUpdated a month ago
non-bliss - On a non-bliss assembly you connect your resistor leads to the two outside wires connected to the blinker bulbs socket as shown in photo below.
bliss equipped - For a bliss equipped truck, you will want to use the blue-green wire (ground) and the grey/brown (power) -or- green/blue (alternate power) for your resistor connection.