I have an older house and I am trying to replace a switch outlet combo in my bathroom with a GFI switch-outlet. I have read the installing leaflet provided, but it does not explain what to do with the red wire in my box only the black and white wires. Can someone explain to me how it should be installed. I also have no ground wire in the line wires.

Does the red wire go the whatever the switch controls?

Does the red wire go the whatever the switch controls?

I am not sure. I tried hooking up the black switch wires to the load terms and the white wire to the load term and the red to the silver and the black to the brass but only the switch worked not the outlet.

You are going to have to get the old switch/outlet unit and figure out what wire went to which terminal, and then hook the new one up exactly like that one.

It sounds like there are only three conductors in the box. If everything follows standard color code and was hooked up correctly and logically, the BLACK wire is hot, the WHITE wire is NEUTRAL, and the red wire would be the SWITCHED LOAD. If there are multiples of black or white, you will then have to do some detective work to determine which black is hot and whether it feeds something else that needs to be GFCI protected or not. The whites then will also have to be connected correctly.

Unless there is something special going on which you did not mention in your post, hookup to a standard GFCI outlet/switch combo then will be as follows. BLACK wire to the brass screw of the outlet and most likely will also be connected to one side of the switch by the brass plate on the side of the unit. WHITE wire to the silver screw which is the neutral terminal of the outlet ONLY. RED wire probably went to the light in the room, and would be hooked to the other brass screw of the switch. Ground wire to the green screw.

Don't just go hooking wires randomly to terminals, sooner or later you will cause a short and ruin the switch. If you can't figure it out from what I wrote, call a professional.

I am not sure. I tried hooking up the black switch wires to the load terms and the white wire to the load term and the red to the silver and the black to the brass but only the switch worked not the outlet.

Move the wires from the load side of the GFCI to the line side. That should solve your problem.