Can anyone tell me where the cable, that originates with the top lever (Air-Fan) on the non a/c heater control panel, ends up. All three levers control doors within the inner heater box, I have figured out which doors the bottom two levers control, but not the top lever as it's cable disappears behind the heater box. Furthermore, my shop manual says that sliding the top lever from the left to the centre opens the Air door and sliding it further to the right operates the 3 speed fan. When I slide the lever from the centre to the right, there is extreme drag on the lever and I'm afraid something is going to break. My understanding is that the travel from the centre to the right side is for operating the fan only. Is this correct? I have removed the cable from the lever so I know the binding does not originate in the heater control panel. I'd appreciate any light anyone could shed on this problem as well as directing me to any exploded diagrams of the inner heater box. Thanks in advance. Joe.