Hello! I have an issue with my bath tub upstairs. The faucet only drips cold water and won't get hot as well. The sinks and my other bath tub works great. The brand is Moen.. Please help!

Sounds like your mixing valve is partailly clogged. Moen warranties them for life so they will send you a new one if you contact them. They also have some good tutorials on their website for how to swap cartrdiges. Installation Help / Animated Tutorials for Moen Faucet