Question: Does the entire dash have to come off to remove the wiring harness? Its on a 1975 f100. I need some good answers. Thank you

 

I don't think so. I have looked at mine and will be tackling the job in a week or two with a new Painless wiring harness. Regardless of which company you go with, here is the link to the manual that came with my harness. It will show you step by step how to do yours without removing the dash.

http://www.painlesswiring.com/Manuals/10117.pdf

 

No, you don't need to remove the dash. Removing the instrument cluster makes it easier. Removing the seat might help too, more room to lay on your back....and being really limber helps too.
Factory A/C makes for more work though.