e39 Reverse Lights Not working

So I have a problem with my reverse lights not working. I can get them working with INPA. I disconnected the Reverse switch on gearbox and cleaned it off and tested it with a multimeter and when I pressed it I got continuity. I put a direct short on the two connections with reverse switch off and the lights would still not come on.

Also before I purchased INPA I put a direct feed on to the two connections heading back from LCM to rear lights and they both came on. So the problem is not the reverse switch and not from LCM back but before LCM. I was reading online and some say it goes through instrument cluster. Anybody any ideas?