MACL-153M & existing 3 way switch wiring issues

Hello, I'm trying to install the MACL-153M at one end of the hallway coneecting two lights to a three way switch at the other end of the hallway

My issue is that the dimmer switch will turn on and off, but will not dim the lights, as well as the fact that the existing three way switch will turn the hallway light on and off but the dimmer will not allow this. Also, once the existing three way switch is turned off the dimmer switch fails to work, (i.e. the indicator lights are out and the switch does not operate the lights). I have programmed the dimmer to 1L.

The wiring in the j-box of the dimmer is as follows. two white wires connected together, with a wire nut, at the back of the box; one "hot" wire (black and taped), coming from the panel; another black and a red wire. The dimmer switch is configured as such, when you look directely at the switch, the brass screw is on the upper right, black screw, beneath that (right side of the switch). on the left side of the switch there is blue screw at the top; and of course there is a green ground wire.

I have the hot wire, from the panel connected to the black screw; the other black is wire connected to the brass screw just above the black screw and the red wire is connected to the blue screw.

The existing switch is a three way switch with the following switch configurations and connections. When you look directly at the existing switch a brass screw is at the top right, a black screw is directly below that. On the left side of the switch is a green screw and below that is another brass screw. Two white wires are connected at the back of the box with a wire nut.

I have the existing switch wired as such: The "taped" black wire is connected to the other black wire in the box with a jumper leading to the black screw; the red wire from the dimmer box is connected to the brass screw on the left side of the existing switch just below the green screw.

I have also tried to wire it where the red wire was connected to the brass screw on the right side of the switch as well.

All of this to no avail. Any solutions?

By default, the MACL-153 is programmed to work with a companion dimmer. If you want to use a mechanical 3-way you have change the setting. It's pretty easy. See link below:

https://www.lutron.com/TechnicalDocu...ary/048459.pdf