Electrical question?

I know I am on a reef forum, but this is reef related.
I am in the process of making a DIY ATO. I know a little about electricity and I think what I am asking is okay to do. So here is what I want to do and I am wondering if this is okay to do, and will it work.

The ATO I want to build show that I need 2 plugs in order to plug in the float switches and the pump. One is the 12vdc Power Supply, and the other is regular 120vac plug. What I want to do is eliminate one plug, the 120vac one. Here is how I want to do it. I will break open the 12vdc power supply plug, and solder two wires to the contacts, before the power goes into the board and run the wires outside of the box, so that I will have both an AC and DC plug out of one. Can I do this?

 

Here is a Schematic of what I am trying to do...

 

Wouldn't you still have the two cords? Or you just trying to eliminate the need for two plugs?

 

With the loads you're working with you should be OK, don't go less than #18. Where is the relay to turn the pump on and off? The cleanest way would be to put the power supply and relays in a enclosure with an external plug for the pump.

 

I am trying to eliminate having 2 plugs. I have to have 2 cords, one is DC and the other is AC.

I used wire that came from an old TV should be at least 18 gauge. When you look at the diagram the top relay turns the pump on and off. I may still rewire this to be contained in a nice little box with an LED and Switch all contained in one. I just have to find something around the house that wont look to ugly when I build it. This is a work in progress.

Thanks guys for the helpful replies. I need to try and find somewhere to salvage the relays, alarm, and LED lights.