Kohler shower fixtures include temperature control devices that attach to the end of the cartridge. This device is a round collar that you as the owner can adjust if your water temperature is not perfect. Adjusting the heat requires turning the cartridge stem a certain direction. This part is easy, the difficult part is taking the shower fixture apart to get to the device. If you have taken apart appliances before, this will only take you about a half hour.
Slide the handle off the faucet after taking out the handle’s attachment screw, which is located on the side of the handle. Make sure to remove the round plug inside the screw hole if there is one before you take this screw out. Use an allen wrench to unscrew the screw.
Take off the faucet’s trim plate and cartridge cover, which is a sleeve installed on the body of the faucet. Unscrew the trim plates two screws with a Phillips head screwdriver and take the plate off by hand to remove it. The sleeve unscrews, by rotating counterclockwise, and you can remove it by hand.
Rotate the stem on the cartridge, the knob on the end of the faucet body to your right or clockwise until the water turns hot. Adjust the knob by turning it left or right until the temperature is perfect.
Unscrew the screw on top of the collar on the end of the cartridge, right below the knob. Re-position the collar so the collar stops the knob at the position where your water temperature is just right. Either tighten or loosen the screw in the collar with an Allen wrench to make smaller adjustments. this screw moves the collar position slightly.
Test and adjust the collar as necessary to change the water temperature as needed.