I have an 08 f150. Doing an Alpine iva w203 head unit. The back of the factory radio has two harness plugs, one is bigger than the other. A third plug is the ant. which needs an adapter too....but the root question is...... The bigger of the two is the harness that adapts to plug into the new unit, what is the second OEM smaller plug for that has no spot to plug into the alpine unit? does it just sit there not pluged in now?

Is the second smaller plug for the steeringwheel controls? is this where I connect the SWI-JACK adapter that allows the steeringwheel controls from the truck to go to the radio? if so, where do i find a harness adapter to plug into this second OEM harness?

 

Yes the second plug is for the steering wheel control. If it's the same as my wife's Mountaineer it will have a yellow wire (the steering wheel control wire) and maybe a couple others.

There was no harness available when I did hers, I had to splice directly into the yellow for the PAC-SWI. The connector was left unplugged and the other two wires aren't used anymore.

 

Steering wheel controls are in the larger 24 pin plug. The smaller 16 pin plug stays disconnected and not used.

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