PB b'laster penetrating oil used in the video: https://amzn.to/3w8ZJi4
Finish line green lube I used: https://amzn.to/2GJ1eNu
Basic overview of reviving a Shimano rapid-fire shifter that won't function. The most common issue with non-functioning rapid-fire or STI shifters is the grease or lubricant originally used in the shifter dries out over time. This video shows how to diagnose and resolve the issue.