This is what you are doing:

The "right" hand holder with the red (10 amp) and blue (15 amp) fuse goes in position 31. In this case, the 10 amp fuse is powering that circuit normally, the 15 amp is feeding power from that circuit's battery feed to the red wire.

The OTHER assembly works like this:
The power comes in on the red lead from the other assembly, goes thru the blue (15 amp) fuse and turns around and goes thru the yellow (20 amp) fuse into your glove box light and cigar lighter. If you don't cut the blade off, power will backfeed into the car and power up stuff that should not be powered. Also, the 20 amp fuse is simply a "jumper wire", it protects nothing, you can use any fuse from 20 to 1,000 amps in the yellow (20 amp fuse)'s position and it won't matter - the 15 amp fuse is the protection for the cigar lighter / glove box light.




In no time, you will be charging your cell phone while at dinner (or, more importantly, your video camera batteries, as the Spring Dragon is coming up!) and leaving your glove box open overnight to guide you into the garage by it's faint light ..... (Yes, I've done that twice now...)