Can't fire up. Buzzing from the relay, lamps blinkin- HELP

[Red]

"over a fuse"
In US English...that works but is, ah, mangled<G>. We use "over" to mean physically above the fuse. We'd say measuring the voltage "across" the fuse terminals, or "between" them. (I'm afraid to ask how the British would say it, we made the mistake of allowing them to retain the right to use a common language when we gained indepence of them.<G&gt

Which is also why the new plastic ATC fuses in cars (including these) have two small holes in the plastic, one above each end. With an ordinary multimeter you can stick the probe tips in the holes to check without removing the fuse. Don't ask me how long it took me to find that out, that is an intentional design.

There's no hard rule for what you "should" measure from the device side of a fuse when the fuse is blown. That will depend on the circuit, and while it would be zero for a simple device--it might not be zero in a more complex circuit, like they've used in cars. Still, 10V sounds wrong for the EFI main circuit unless something is shorting into it.