DRLC light fixture wont loosen

You might find yourself trying to loosen the knob to remove the light fixture on your DRLC unit. Inside of the fixture there is a a washer and a nut on the plate which unfortunately you will not have access to unless the whole fixture is off. It is likely that the nut is loose on the rod and that's why it is spinning and the knob will not loosen up. Carefully, spray a lit bit of WD40 on the knob and that may help to loosen the knob and allow it to spin. More than likely when the unit was installed, the installer left the nut loose on the rod which make removal very tricky and difficult.