I have a 98 CLK and am having trouble figuring out the overrides on the Climate Control System...specifically overriding the register selection. For example, if I take it off 'auto' and have the two thermostats set at the lowest setting 'LO'..then the air blows out the center dash vents...no matter how I push the button(s) to change it to the defroster or floor vents. If I move the temp up to a higher setting, then the register overrides seem to work. Also, I can't figure out how setting the left side and not the right makes any difference. Can you clarify how these should work? The owner's manual gives very little info.