Electronics » Nav V GPS: auto screen brightness fluctuating

I've noticed this happening when it starts getting dark; was particularly bad this evening - while riding at around dusk my Nav V screen was essentially cycling between 'dim' and 'very dim', every few seconds. Barely bright enough to see clearly at any time. Was fine when I switched 'auto' off. Any thoughts? Where does the device get its light levels from - the bike?

I've not seen this happen myself, but if it's normal, the likelihood is that the light level being detected is hovering at the threshold of the two illumination triggers.

My Nav 6 does this quite a bit but I just accept it's on the cusp of switching over.

Like my car headlights switching on and off when going into shaded sections of road at dusk