[redrider044]

I have a '78 928 that is missing a heater A/C control knob. I ordered one from Pelican along with the retaining clip that is supposed to fit all 928's thru '86 but it doesn't fit my '78. The stem/shaft part that should fit thru the control panel is too thick. I called Pelican & they said the knob for a '78 is N/A. I returned the part & ordered one directly from a local Porsche dealer & it was the same part. What do I do to get this part to fit? Do I file down the replacement knob or get a later model control panel or ???? Once again, many thanks for a great forum.