I found these laying in the engine bay fuse box. I was replacing my battery today and I thought I would take a look and test some of the fuses because… I’m always looking for solutions to problems that don’t exist. (Actually, I was checking because I have a few switches on the interior dash that aren’t working so I thought I’d test the fuses.)

What are they?

 

I had a hunch, when I saw the parts and I confirmed it with a browser search: Those are "dust covers" or space-holders (so that you don't accidentally put a fuse in there) for unused fuse locations:

 

Actually....If there is a fuse under the cap, it is there as a kinda 'tamper-proof' indicator that the fuse should not be messed with like an AIRBAG fuse or similar.

All mine have fuses under the caps.

 

Thanks!

 

What motorcarman writes, makes even more sense.
Thus, those covers are waring signs to only remove THAT fuse under the cover, if you know, what you are doing (airbag).

 

yeah, none of my fuses had a “cap” under it. They were all exposed. The “ caps” were just laying in the fuse box as shown in my picture.

If all of your fuses had caps on them, and you didn’t put them there, then clearly, someone at some point in time, had pulled a lot of fuses!!

 

> yeah, none of my fuses had a “cap” under it.

OVER: ...none of my fuses had a cap OVER them... (Greeting from George W. Bush, again, too...

I actually think that the original idea must have been that those YELLOW caps are on top of all airbag related fuses, because the colour YELLOW generally stands for everything airbag-related (airbag connectors AND CABLES are also yellow). Thus, it would fully make sense to cover all those airbag related fuses with a yellow cap, as a warning, e.g. not to pinch a fuse from there, just in case you are short of a fuse somewhere else...

 

Yeah I'm sure there's a few in mine with fuses underneath as anti-tamper covers too.