I couldn't find all the proper information on how to do this so I figured I could contribute and hopefully help someone else do this in the future.
I have a 2002 Outback with the double/split headlights. I purchased the 2004 headlights with the 9007 headlight bulbs. Obviously they aren't the same and thus the harnesses have to be swapped and rewired.
Before and After. Top is old, bottom is new.
https://www.dropbox.com/s/usqvjaglh6yq71p/Photo%20Oct%2017%2C%207%2056%2050%20PM.jpg?dl=0
I first ordered the harnesses from Amazon
ACDelco Professional LS256 Headlamp Socket:
https://www.amazon.com/dp/B001DRN63C/ref=cm_sw_r_cp_api_glt_fabc_VQN7K92GT8MBSWPPTABX?_encoding=UTF8&psc=1
https://www.dropbox.com/s/s6pxbncv6vicztp/Photo%20Oct%2017%2C%208%2048%2025%20PM.jpg?dl=0
Next, the wiring setup.
From the car harness, the wiring is as follows:
Yellow wire: Low beam
Blue wire: Ground/negative
Red wire: High beam
With the harness facing you female end, and in a upwards rainbow shape, the following is how the wires must be connected and I've attached a picture.
https://www.dropbox.com/s/0ndkt8ns8fqifxs/Photo%20Oct%2017%2C%208%2055%2027%20PM.jpg?dl=0
Left: High beam
Middle Up: Ground/Negative
Right: Low Beam
I hope this helps everyone. Cheers.
