@cadsys Thanks for this! Glad you got it working. I think I can see where the confusion was, in that pin 41 is the Z_PROBE_MOD_PIN, which isn't used by BLTouch. The servo needs a PWM pin, so the heater pin is ideal, but it's not specified. The black and brown wires are, apparently, a shared ground, so you only need to connect one of them.
I'm about to update the BLTouch documentation, which has outgrown the 'Connecting a probe' page, so is going to get a page on it's own, and I'll add this info.
Nice to see a RepRapPro Mendel still going, even if you have reprinted some of the parts! I probably crimped the wiring looms on it...
Ian