You didn't give me any directions. Below is my original question along with your response. Had you read my question in advance, you would have seen that there are NO red wires coming out of the wall, however, your response is posted below mine.
My original question was this, "I have a light switch with three black wires and three white white coming out of it. I want to put a dimmer on that outlet. The dimmer either has two black plus green ground for a single pole OR two red, one black plus green ground for a three pole which is my first choice as this new switch has a toggle and a lever to control the dimmer. How do I attach the dimmer to these wires? Unfortunately, I already removed the switch and don't remember which wire went where."
Here is your initial response: "Hi, I'm Mike and I'll be glad to assist you. I read the conversation with the previous expert and can only assume that you use ther red wire for connection to the house wires. That would cause exactly what you described. Use the black dimmer wire to the hot and the unknown black wire and one of the red dimmer wires to the black wire to the light. Cap the unused red wire. That should resolve the issue."
To answer your recent follow up question, because I tried so many combinations to get this dimmer working, I don't recall what happened exactly. I have one of each of the black wires attached to one of each of the wires in the dimmer. My final combination allows me to dim the light and turn it on and off as normal. NONE of the wires got capped off. The three white wires in the wall that were capped when I opened it up remain as such.
Unless you are saying to do the same thing similar to what I have done, I don't understand your initial response. The only red wire that come into play at all are on the three pole dimmer switch.