Sorry about your door-head collision. No pain....
From here on I think having a multi-meter is necessary...or at least helpful. You need to see if your getting voltage and where. And using continuity, you can tell if you have an open circuit or closed. Do you have a multi-meter that has a buzzer for continuity? If it is making connection it will buzz and have a zero resistance, thus you have a connection. If silent, there is no electrical connection.
Re cleaning, take your connections apart and use a knife, file or stiff wire brush terminal cleaner to take any built up corrosion off. You will likely go through the crimp-on connector's silver coating and see the raw copper. On the lead parts, go to shiny metal on the lug and the terminal. Make flat surfaces where the bolts have dug in. Of particular importance is the battery wire to frame connection, they build up an insulating coating at the copper to steel face and both must be cleaned to bare metal for a proper connection. I use anti-corrosion electrical compound as I put it back together, giving each bare metal surface a good coat so corrosion will not form again. I even put washers on my bolt heads and nuts to distribute the joints pressure over the entire contact area. It prevents the bolt head or nut from deforming the connection and giving less surface to contact. You want a lot of (clean) surface touching that has full contact.
Have fun with your green truck...when your headache goes away.
