When trying to repair a shower faucet by Kohler, start by unscrewing the trim's screws and removing it along with the caulking; this allows you to inspect the system. Before removing the trim, it's important to turn the water supply to the shower off.
Shower faucets are fairly simple devices, and problems relating to dripping, poor temperature control or poor water pressure are often due to the valve. There's no standard faucet valve; each manufacturer has its own technologies, and the same manufacturer might use different types of valves on different models. However, the faucet seat sometimes becomes loose over time, and replacing it might allow you to avoid paying for a whole valve kit.
Before removing the trim, it's important to have caulk on hand to reseal the trim and prevent water from leaking into the walls. Faucet valve seats often require specific wrenches; attempting to remove the seat without a seat wrench can cause extra damage. Fortunately, shower valves are generally straightforward to replace since most use cartridge-based designs that allow for simple replacements. When attempting to inspect the system to find out which item to replace, exercise caution to avoid completely breaking a system that still partially works, especially if parts aren't available locally.