OK, so I had an existing wall switch that I added to so I used the existing power coming in to add the new switch. I've drawn a diagram of what have wired so far.

I am trying to wire this new GFCI (also weatherproof and tamper resistant) receptacle so that one of the plugs will always be hot and one will be hot when a switch is turned on. I found a simple diagram online that solved this for someone else.

The GFCI will instantly reset if the white wire going to the load side in the diagram of the GFCI is connected. If I remove any of the other black wires or the remaining white, I get the results expected (the receptacle would work as expected or not have power, depending on what was connected). Just when the white wire is connected is when nothing works.

I am not sure if this means I have a problem with the white wire somewhere? All of my tests for voltage found it in the right places and the ground seems to be working fine. I am stumped

 

That is not possible with a GFCI receptacle. There is no way to split the plug-ins.

 

We could help you do this if you wanted to install a constant hot GFI and another switched GFI.