It also does the low and high speed engine cut out and probably the voltage cut-out etc.
According to the gas klima on my desk pin 7 is term 87 and 10 is the PBC signal. Early 190D Klimas used power from the PBC to control. I am not sure how many models used this but I tell everyone dealing with KL to view whether it is a ground or 12v signal before by-passing. I have seen a number of PBCs with burnt circuits due to grounding the KL signal at the low pressure switch.
In order for your jump to work you have one of these rare powered KL circuits. I would use this KL as the 86 terminal in a "ice cube" relay and place 7 on the output 87 terminal of the relay. Term 15 can be used for the load carrying power (term 30 on relay) and 31 can be hooked to 85 on the relay.
I would not leave the circuit as you have jumped as the circuit is not designed to handle the load of the compressor clutch. It is a 100ma circuit at most and the clutch is at least 3amp (3000ma) circuit. That circuit is carried on the small printed circuit of the PBC.
Bosch Master, ASE Master, L1
33 years MB technician