After a BSI swap , as part of a tacho removal process, Howard used this correction box to get the speedo accurate again. With coding being so tricky on these , this was a quick & cheap solution. The yellow plug he’s refering to would is what previously was plugged into the tacho
“Hi Martin,
Recently bought a Chinese black box to sort out the mismatch of gearing on my van, from eBay. It was excellent!
Apologies if this is old hat, but it was a case of pull the yellow connector apart, and the part with 3 wires, green 12v, brown -ve,
Orange signal, cut and join orange wire attached to plug, to box blue wire, and flying orange wire to box yellow wire, and reconnect yellow plugs.
Drive down the road with gps speedo App giving true speed, then adjust the box with 2 buttons, to give a match with vans speedo, and that’s it. The box displays the mismatch, and I ended up with a 1.27 multiplier displayed in box.
The only thing I haven’t fixed is why the speedo refuses to display anything until i am doing 15mph . I think it could be low voltage supplying the speed sensor.
Sorry, I had to tell somebody, as my wife could not grasp the significance of the tumultuous event!!
