Will lowrance still repair the HDS gen 3 touch units?
Without calling them and asking, my guess would be no.
They will probably try to sell you a upgrade.
Lowrance is quick to stop working on the previous stuff. I have a gen 2 and the software quit reading the satellites two years ago, location and clocks wouldn't work. The told us they consider these units legacy and they won't be working on a fix. There was such an up roar that they did provide a fix.
All this to say, if your not running carbon's they probably won't help. But like Nutoy said, you won't know until you call.