Reddit reviews Gardner Bender 10-121N wire terminal, 100 Pack, Red (22-16 AWG), 4 Piece

Do you know what wiper motor you have? Or what year and model car it came from? From that we can get the amperage.

Voltage doesn't matter-- everything is 12 volts (DC).

Amperage does matter, but I'm guessing your wiper motor uses around 1A. The relay of the remote I linked to earlier has a rating of 5A, so you might put a 5A fuse in there. If there's a short, it will definitely go above 5A and blow the fuse (which is what you want). Here's an example of a fuse holder that would work, but there a million options.

Since you're using a 5A fuse, you could use 16 or 18 AWG wire (rated for 7 and 10A).

So far I've been talking about the circuit for the motor that passes through the relay. For the receiver's power, you could use another 5A fuse with the same wire just to be consistent, though it really is only using milli-amps.

So basically, we size the protection (the 5A fuse) above the normal operating current (1A?), and then everything else is sized to be higher than the protection (5A+).

Finally, you'll wonder how you're supposed to connect the wires together. The best option is to solder the wires together and put heat shrink around the joint. If you can't handle that, they sell crimp wire splices for that. You can buy a real crimper or just use pliers.