This will not answer your question, but if you intend to operate the fan and the light separately where there was only a light before, you will need to run 14/3 wire so that you can have two switchable hots instead of just one.

Unless you intend to use one power switch on the wall and two pull-chains (or similar) on the fan/light.

You CANNOT separate the fan and light from the wall the way it is now. At this point you have two, actually three, options. #1 is the most unlikely at this point.

1)Re-wire from the wall box to the fan and use a dual control at the wall box.
2) Do as you suggest and replace the dimmer with a switch and use the pull chains on the fan.
3) Do as you suggest and replace the dimmer with a switch and get a universal remote for the fan.

In replacing the dimmer, don't be confused, just install the switch the same as the dimmer. Don't let the colors confuse you. You may need to pigtail from the splice to the screw terminal on the switch.

Hi guys: Thank you for your prompt response. Both of you have good recommendations. All I want to do is replace the dimmer switch on the wall for a single on and off switch,because the fan already have two pull chain switches for the fan and the lights,but I was confused by the multiple wires connected to the dimmer switch. So basically what I need to do,if I understood correctly, is to attach one wire to the black and white wires from the wall to one end on the single switch,and another wire from the other black wire from the wall to the other end of the single switch.
Thank you guys for your assistance.

Thank you guys.I followed your recommendations,and I replaced the dimmer on the same spot with the single pole switch,and the fan and lights are working fine.

Thanks again!
Take care