
Here is where the rear light wiring comes down the frame by the driver's side rear wheel.

Does this look in good order?
Now, when it gets to the rear bumper, we have this disaster.

Am I right in assuming that I just need to figure out which wire lights up when I press the brake, switch to reverse, or turn on a signal and then hook up the corresponding wires?
If so, when I splice in the wires, should I soder then together and then use one of those plastic covers that your crimp, a cover that you shrink with a heat gun, or is there something else more prefferable? I am interested in doing it the right way one time, so advice is welcomed.
Thanks in advance.