p 38 heater

1999 p 38 manual diesel 133,000 miles Digital hevac unit
Hi all
I'm struggling with my p 38 heater directional output. I cant seem to achieve the correct flow so to speak, when I press the up button it will direct the flow to the screen ok. When I press the button to the chest height button I get some flow but still get air to the floor. My nanacoom says fault 55 ,over current motor stall. I've changed the servo for a good one ,cleared the fault and it still happens. I took the servo off and the white wheel is quite stiff to move. The very front flap on the dogs leg moves ok and easily , as does the black top one. The rearest black cog seems stiff, if there any way I can lubricate this flap? Can I pull the black cog off? Once assembled should the white wheel move easily i.e with one finger?
Thanks to anyone who has any input

It is the rearmost flaps that seize up on their shaft. The black cog is not removable without damage unless the shaft is moved to the right and the cog is out of it's bearing, which cannot be done without stripping heater. It maybe possible to get in and lube the shaft by removing the bottom rear panel. But if it is possible it will be a fiddly job. The white quadrant also gets tight on its pivot. Be aware there are marks on the front and rear cogs that MUST be lined up with marks on the quadrant in each direction correctly on re assembly. Or the quadrant maybe destroyed in operation.