Bearkats99

I have a 2008 Cobalt and recently the driver side headlight was going in and out. I then noticed the connector looked like it had melted and assumed created a bad connection. I replaced the the headlight connector harness (three plugs) and that did not fix the issue. I then replaced the connector from the electrical lines that plug into the connector harness and that did not fix it. I am now thinking after more research it must be a bad ground wire or earth wire. The issue is that it appears the ground wire for the driver side headlight is under the radiator overflow tank. I was trying to see how to remove that tank to give me space to inspect the ground wire. Does anyone know if I have to remove the fuse box in order to move the reserve tank? Also, does anyone have any other ideas pertaining to the issue of the dim light?

Thank you!