When I needed to add an extra feed to the reverse light bombtail I twisted a good bared length around the outside of the hollow crimp MMC use then soldered in place using my larger 80 watt iron. I flooded the crimp with solder as well then finished job with a couple of layers of heat shrink.
I imagine most bombtails (splices) use the same crimp tubes with bared cable ends poked through (maybe twisted together) then crushed by flattening one end of tube.
Mark, I can confirm that VSS signal on brown/white wires shared via bombtail feeds VDO gauge directly on pin 19 as well as pin 86 on ECU. This would explain why speed display remains when OBD readout fails.
