Have you checked that it's not just the screen brightness that's been set (or moved??) to less than 100%?? :dontknow:
My 2013 RTL that lives in the harsh Ozzie sun hasn't got any screen fade issues (yet!

) except whenever, for some inexplicable reason, the brightness drops to 40% instead of the 100% I usually leave it set to! :gaah:
And occasionally it doesn't seem to 'engage' properly in its mount, so it doesn't connect to the Spyder battery & charge during use; resulting in the onboard battery starting to go flat.... & the first sign of that occurring is the display dimming.... :banghead: Usually, taking it out of the Mount & re-inserting it properly sorts that, but every now & then I don't do that soon enough, so the Zumo completely conks out, which then means that I hafta take it inside & charge it up using the update/charge cord & a PC or mains charger.
Still, if it's not something like that then you'll probably need to upgrade the GPS to something like a ZUMO XT or XT2, and that'll mean you need to swap the Garmin base & wiring in the Spyder mount. It's not really all that hard to do, I've done a few for others, but it does involve removing the base from the mount (a few screws), the LHS tupperware, & disconnecting the wiring (usually the plugs are down alongside the gas tank), before pulling the wires & GPS base out. Then you hafta re-thread the new wiring & connect it up
*, before fixing the new GPS base to the Spyder mount & buttoning everything up. :thumbup:
Nb: * the generic Garmin wiring plug on any new Garmin GPS is often at a reverse polarity to that in the Spyder's Garmin power connector (I guess that's done to make the CanAm GPS units unique to CanAm!

) so you might need to swap the wires in the plug to get your new GPS to charge - it's fairly easily checked if you know how to use a multi-meter; and if that's the case, then maybe it's not quite so easily remedied, but it's still not majorly a pain - just so long as you're aware that it
might be something that needs doing! :thumbup:
Good Luck! :cheers: