The MIDI data the wheel is sending out if I run MIDIMonitor seems to be working fine
The wheel itself and AD converter are fine.
If the mod wheel is set to "LFO Amt" it seems to work okay
DA converter and destination switch LFO position are fine
Both cutoff and vibrato seem to work just fine with aftertouch controlling them
both functions seems to to be fine
Cutoff -- doesn't seem make any difference what the wheel is set to. It just doesn't affect the sound at all.
Modwheel position is added to cutof knob position. Be sure to set cutoff at low level to get an effect from the modwheel.
Vibrato -- vibrato is the same (max) no matter what the position of the wheel is set to.
It's very surprising because the the default vibrato amount is 0 when mod wheel is not connected, and mod wheel value when connected
Sorry I have no idea on this one, according to your description every sub-part seens fine, but the whole thing is not...
you should contact the seller for a repair or replacement