You have to battle your way up the two staircases and turn off the waterfall. Only one of the staircases leads to the switch, though. The waterfall will turn back on if you leave the gym.
The fifth gym leader is Pokemon HeartGold SoulSilver is Chuck. He is in Cianwood City, but in order to get there you need surf.
To the MOON!
were is the fifth gym leader
you go to Petelberge city and talk to your dad.
You have to go to cianwood city in the pharmacy and talk to the guy there.
The third gym leader is Whitney.
The fifth gym leader is fantina.She is in hearthome city.
The final gym is the Viridian City Gym. Blue is the Gym leader.
travel up the left side of the gym and hit the red button at the top
first it's not your rival and second the gym leader blue can be found on cinnabar island if you have all the other badges talk to him.
Well after you defeat 15 gym leaders in Pokemon HeartGold / SoulSilver go to Cinnabar Island and talk to Blue.
Firstly, have to defeat the 7th gym leader. Then you go talk to the trainer next to the Pokemon center on Cinnabar Island. He is the 8th gym leader of Kanto, Gary. Gary is in Viridian City.