Pop-ups shouldn't be a problem with these documents - they're direct links to PDF files.
The 7-pin wiring diagrams were built in an Acrobat version higher than 5 (probably 6), so in Reader 5 they produce a warning message, but still display properly. An even older Acrobat Reader (either separately or as a plug-in into the browser) may not display them at all. Every document in this section of the Document Centre is a PDF, so if the other ones work and these two fail, then I would suspect that you just have a very old plug-in; fortunately, that's a free upgrade from
Adobe.