If by main lights you mean the headlights then yes. All switches should be backlit when your headlights come on!so you can find them easier in the dark!
Proud owner of multiple transits! Campervan: 2000 Transit VG MK5 - 2.5 Di -85ps - Auto - LWB Cab Chassis: 1999 Transit VG Mk5 - 2.5 Di - 100ps - Manual - LWB "Spare Parts Van" 1997 Transit VG Mk5 - 2.5 Di - 100ps - Manual - SWB
I’m fairly sure that if you fit Granada 1993 ish that they work but don’t light up I tried it and it didn’t light but maybe the Granada switch was broken but I did try a few I had and none appeared to light up like the correct transit switch’s they did work ok but didn’t light up with the side lights