Lighting Switch - 29DA in Dodge & Dodge Brothers Posted September 17, 2011 There should be a compression nut at the switch end of the light switch control tube. If this nut is not tightened properly, the tube will rotate, but the rotary Clum switch won't. Usually this gets loose due steering box gear oil soaking the entire assembly. Since this is a compression fitting, excess gear oil will cause slippage. Another possibility is that something's amiss at the top end of the control tube up near the horn button. Simply having an assistant observe the tube at the switch end while you rotate the lever inside the vehicle should sort the problem out.