Route colour

I have a route in zumo 346 which shows in black but has a short section which is magenta ,so will the directions be given for whole of black route or will it give directions to follow the magenta section?

 

Well I found the simulation and ran it,it turns out the satnav will give directions to follow the magenta route.Which begs the question,why create a route in basecamp and upload it, if the directions from sat nav will overide it.Also why why no mention of different coloured routes in user manual or Basecamp?

 

Well despite quite a few emails backwards and forwards with Garmin support I finally found out for myself what was causing getting the black route.It was gpx routes that were in the Zumo's internal storage ,as soon as I cleared the files the black route disappeared,but how or why they were being overlaid on my route which was a saved trip I haven't a clue.