I bought a Squier Vintage modified series Telecaster from a friend a while ago and don't understand how the volume and tone knobs. I noticed, when I was using the single coil pickup that the one of the two tone knobs controlled the volume and didn't seem to do anything with the humbucker pickup. Also one of the volume knobs controls volume with the humbucker pickup and does nothing with the single coil pickup. Is this normal, or is something messed up with the wiring?
Assuming it's the Tele custom model with 2 volumes and 2 tones, yes, that's normal. one set of vol/tone knobs is for the bridge pickup and the other is for the neck pickup. That's why there's 2 of them
Live Rig January 2018

Fender Baja Telecaster/Danelectro DC-12
Boss TU-3, Ibanez TS-9, Fulltone OCD 1.7, EHX Small Clone, MXR Carbon Copy, EHX Holy Grail Neo
1964 Vox AC30TB with '69 Rola G12M "blackbacks"
Elixir Nanoweb 10-52 strings, Dunlop Jazz III XL picks