What is this connector and why am I mad at it?
 

Hey everyone. I'm having trouble with the connector pictured below. It's right next to the positive batter post and the cable appears to run from the fuse box to the starter. I could be wrong about that. Oh yeah, 2005 Elantra hatchback.

The problem I'm having is that I'll go to start the car and there will be no power to anything. Battery is good but no dome light, no radio, no blower, no dash lights, absolutely no power to anything. I'll leave the key in the "on" position and then go fiddle with this connector. I hear relays click, the blower kicks in, the "hey you left your key in the ignition and the door is open" noise starts... you get the idea, and then it starts up just fine.

Once the car is running it stays running. When I hit a big bump the dash lights and blower will drop out for half a second and then come back on. The charging system seems to be fine too. I haven't killed the battery yet. It's just annoying to have to open my hood every time I start the car and I'm worried about this problem causing other problems. Thoughts anyone?