I have an ad unit on all the pages of my sites that I want to pause for a test. I want the other 2 ads to remain active. Is there a way to pause an ad unit versus having to manually remove the code from each page? How am I not seeing a way to pause this ad unit?
There is no way provided by Google. The only way to pause it is to manually remove it from your site.
If you want to actually pause ad units, you need to employ an advertising delivery system system that will let you do it on your end. For example, I use a WordPress plugin that lets me specify a schedule or deactivate a placement temporarily.
But Google doesn't offer anything in their standard AdSense product. There may be something in DFP, but I don't use that so I don't know for sure.