Thanks for your advice! I had thought of that, as the pins seem to be split in 2 towards the top, suggesting a captive type nut could be pushed on, and stay in place by the potential pressure of the 2 split type pieces maybe springing back to keep it in place. However..... here is the issue/s - the pin in question seems to have one of the 2 top pieces missing, and when that particular control/pin has the cable attached, and you attempt to slide the pin towards the drivers' side the cable becomes so resistant, that IF it wasn't allowed to slip off the pin itself (i.e. if there was a captive/push on nut in place), I fear the pressure exerted on the pin would end up snapping/breaking it altogether :(... So I'll just have to trace the cable / mechanisms/flaps etc to see IF there is something else untoward causing such pressure/binding in the cable, if possible, without having to remove the heater box..... wish me luck!!
