I have labeled the wires from.the repair manual.

Last night I found this splice when attempting to fix my speedometer. After replacing everything, I had to work the next day, so I left it for another time since the car ran fine. The next morning I drive to work, speedo working flawlessly, as well as my oil pressure gauge being much more responsive, I get to work, shut off key, but the engine ran for a few more seconds, before running out of fuel and dying, leaving the dash lit up like the key was at the run position. If I wiggle this splice after turning the key, the car shuts off like normal.

My questions are
1. Do I keep this splice, dress it up with solder and heatshrink, and not fix what isn't broken (since it runs like this)

Or

2. Why would the previous owner splice these together, and if I wanted to correct it, what other bypassed components should I look at.