Hi can anyone tell me who makes the factory nav head unit?

Well, its a little complicated...

This was posted on another board.

The shipping version of the THX/Nav systems for the LS (and other Lincolns) is being produced in Taiwan by a joint venture between Pioneer Electronics and Nippon-Denso. Apparently the Visteon/Alpine system in the original test mules (and which was used to re-engineer the LS interior to meet THX Premium Auto standards) could not meet the target price point for Lincoln's sales model and Pioneer/Denso won the bid. I understand that the Nav unit and electronics are designed by Denso, the in-dash CD and radio system are built by a division of Pioneer in Taiwan, the amplifier and speakers are manufactured in China by the same company that produces Clarion under contract from Pioneer. The individual components of the Pioneer-designed system are not THX certified, only the complete package as installed in the LS (which means Pioneer cannot re-sell or re-package the components and list them as THX certified.)

If I remember right, you can pull the bottom package tray lining off and on the bottom of the DVD player there are Ford and Denso part numbers.

it's simple. the head unit is pioneer. the trunk unit is denso.