I have a bryant central heating and air system, I turned on the ac one night and it fliped the fuse, so I went and turned it back on and now the ac compressor runs for like 15-20 seconds then shuts off the blower motor is working but the return air vent isn't sucking any air at all. Im not sure if the giant fan you see on the back side of the unit is the one I need to replace or not. Model number of the unis is 30-579A

You have a blower fan in the inside unit, If it is not working, you will not have return air, you need circulation. The Air Handler Blows cold air through the ducts, it does not Suck air in.
The Compressor and Compressor Fan are outside, can you give more info?
Back side of what unit?

I opened the side of the heating and air unit and turned on the fan and the blower was blowing , but when I went inside and checked the return air vent its not sucking anything. On the house side of the heating and air unit is the vents going in and out of the house on the other side there is a fan that you can see , that's the one that I don't see turning. Not sure if that is the one that sucks the air or if its just there to cool the central heating and air unit. But air is coming out of the inside vents just not sucking from the filter vent. I opened it and took the filter off and its not pulling any air in.

Is your complete system outside?

Yes

If you can't find the leak you may have to disconnect the duct work at the unit, Is it the coiled duct, would make it easier.
I think it either has to be blocked or, leaking.

Well there are two ducts coming out of the unit into the house. One is for the air in one is for return I was wondering if there were two fans, one at the duct to blow air in and one at the duct for the return air, and the return air fan is maybe out.

Basically the return air is releiving the pressure by the blower, blower blows out, the air has to go some where, so instead of building up pressure, it is sent back to be cooled again.

We have 2 return air upstairs one is sucking air and the other does not.

You have a blower fan in the inside unit, If it is not working, you will not have return air, you need circulation. The Air Handler Blows cold air through the ducts, it does not Suck air in.
The Compressor and Compressor Fan are outside, can you give more info?
Back side of what unit?

You have a restriction in the air ducting