2000 a/c controls

My daughter had a friend put a new radio in her elantra. I don't know what got abused when he did it, but the a/c doesn't work now. When you turn the fan to any speed, the light on the rear defrost button lights. If you hit the def. button, it doesn't stay in.....(should it ?). The a/c button does nothing, no light whether it is pushed in or not. All the fuses check out ok. I can't find a wiring diagram anywhere, library, auto parts store, etc.. Does the power for these controls go thru the rear def switch, and maybe that is bad ? Any help is appreciated........

i dont know much about the a/c controls but, when they installed the head unit did they use a in dash install kit or wiring harness? or did they hard wire the radio into the car?? and if they did either they might have crossed or miss wired the unit..

You should remove the center fascia to remove/install a radio. Several cables are attached to the rear of the center fascia using plugs for things like a/c, emergency switch, rear defroster, and so on, and at least three of the plugs have the same pattern. If my memory is correct, the connectors for a/c and rear defroster looked identical. It seems to me that your daugher's friend either forgot to connect the plugs or misconnected them after installing a new radio.