Here’s what happens to a wire in a Jeep after being connected with one of these things for a while. Yep, it failed. Thankfully this was only an auxiliary light, but I’ve seen electric engine fans, fuel pumps, and other things wired in with these things. Guess what happens? Oh, and the other fun part of these things is that they aren’t even a little weather proof. So, even if they don’t cut through the wires totally, in basically anywhere but the desert, the wires will start to corrode the second you install one.