I understand. I do in fact have the round white connectors in my L99

I am just trying to figure out/understand exactly what the adaptors do:

I know they plug in to the NEW '08 up style mirrors, and have the round white connector to plug into my L99 wiring-that part I get-I would also like to know what the smaller BLACK plug would go to......looks in the pictures like it has 2 wires in it.......anyone know what its intended for??

 

Not sure if this is what your looking for but here is a write up that I did last year.
Not sure why but on my truck the color on the wires were different from driver to pass side. The picture that I gave you the wire is blue.

All the wires can be ran under the dash and do not have to go into the engine compartment. I have the e99 so my plugs did not even come close to the stock one and had to build my own Delphi plug kit. Pretty simple plug to build. As for the wires coming of the mirrors, there should 7 wires coming out of the mirror side.
BLACK/WHITE-HEAT
BLACK-GROUND
WHITE-TURN SIGNAL
BROWN-RUNNING LIGHTS
PURPLE, YELLOW, GREEN should match the factory wiring for the mirror function.

On driver side for left turn signal go into the wire harness under your steering wheel which should be raped in electrical and wiring loom peel that off and tap your white wire into the green/white for left turn.

For your pass side mirror turn signal will also be white, that wire will also go under the steering wheel and tap into the white/blue wire.

Driver side running light would tap into the brown wire behind the headlight switch.

Passenger side running light can be tapped into the pass floor kick panel. Take that panel off and find the factory wiring harness only two wires, a black for the ground and brown for power to the outside cab lights. If you don't have the roof lights the wire harness should still be down there and will end with a female plug.

Heat wire, I built a fuse/relay panel under the hood with a bossmann fuse/relay block to run the switches that I have in my F-650 dash panel. Run the black/white heat wire from the pass side mirror to a relay along with driverside to the same relay. Run a switch from your dash to that relay, ground and power the relay.

RELAY numbers: 85-to switch 87-to fused power 30-from heated mirrors 86-to ground


There is probably a better way to run the heat into the relay but sense there were to wires from both mirrors I just tied them to gether at the relay.

I ran the turn signal and heat wire for the pass side mirror behind the dash using a snake feeder to hide them as clean as possible. its much easier to get behind the glovebox if you remove it pretty simple.

Pics are in here and go to thread #6.
https://www.ford-trucks.com/forums/1...l#post13613546

 

Thanks Scott!! This DOES help!