Very little air coming out drivers dash vent

[dmwelch54]

W164 ML320 2005. The other vents are fine. Cycling vent button makes no difference to the drivers vent. Are there separate motors for the 4 vents? I believe there may be dislodged pipe or if there separate flaps for the 4 vents, haven't a clue. Without taking the dash apart thought about taking the radio out to see if I can see the vent pipe. There has been some tinkering by previous owners I'm number 5. Point is SAM in the boot being out of it's mounting and as there is factory towing hitch the codes to let the trailer lights wasn't active. Any thoughts? Dale