I have two wires on Hunter fan/light switch 27186 that are both black and I bought Hunter 27182 switch to replace it and it has red, blue and black wires coming from it. How am I supposed to install 27182?

The 27186 is a two wire switch. It controls the fan on/off and speed through the wiring. It controls the light on/off and brightness with radio signals to the receiver in the fan canopy.

The 27182 is simply a fan switch and a light switch/dimmer combined and requires three wires to the fan/light, a neutral, a fan hot and a light hot. Unless you have a 3-wire cable between the switch location and the fan/light you can't use the 27182.

Ebay shows the 27186 as weighting 2 lbs, therefore it must include the switch and the receiver. The switch alone would not weigh 2 lbs.