When doing replacement or upgrading on 1973 – 1974 Volkswagen Thing, the bulb size guide is necessary for you to take the reference.

1973 – 1974 Volkswagen Thing Bulb Size Guide
High Beam and Low Beam Headlight	1973 – 1974	H6024
Back Up Light	1973 – 1974	1156
Brake	1973 – 1974	1156
Dome Light	1973 – 1974	DE3423
Front Side Marker	1973 – 1974	T4W
Front Turn Signal	1973 – 1974	1156
License Plate	1973 – 1974	12821
Parking Light	1973 – 1974	12929
Rear Side Marker	1973 – 1974	T4W
Rear Turn Signal	1973 – 1974	1156
Tail Light	1973 – 1974	12821
Courtesy	1973 – 1974	DE3175