Y/Bl is the tach signal from the ECM to the cluster (didn't bother to check if it's used elsewhere). B/W is the ground. Those jumpers are probably associated with bad contacts in the nearby connectors. Rather than fix them, the PO cut the wires and jumpered around the connector. I can see what looks like the remnants of the cutting on the black connector. You need to fix those cludges.
I have limited knowledge of K1/K2 but suspect that the yellow and black connectors are associated with the connection between the main and front wiring harness. That connection has long been a source of problems, finally fixed in K9 when they switched to a sealed connector. You probably ought to take a close look at the connectors with regard to any evidence of contact corrosion. Some dielectric grease would be helpful.
I have limited knowledge of K1/K2 but suspect that the yellow and black connectors are associated with the connection between the main and front wiring harness. That connection has long been a source of problems, finally fixed in K9 when they switched to a sealed connector. You probably ought to take a close look at the connectors with regard to any evidence of contact corrosion. Some dielectric grease would be helpful.
