For the rear all the bulbs are single filament, 21 watt for stop, turn, reverse, 5 watt for tail lamp. Small bayonet for the license plate. All turn signals common fuse, brake lights fused I think with the horn, taillights fused right-left side. Look for a bad ground. 
Why are you looking on the internet? Where is your Bentley? 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John H. Lauterbach
Sent: Monday, September 23, 2019 7:20 PM
To: vanagon@GERRY.VANAGON.COM
Subject: '91 GL -- no brake lights, no license plate lights, but have tail lights, directional signals, and back-up lights

I went to the FLAPS this afternoon and got a complete sent of Sylvania bulbs for the rear lights.  All the numbers matched what has been posted on the Internet, but a couple of the lights look different than expected (two contacts instead of one), and tail light bulb was same wattage as stop light bulb (on my other Vanagon's stop light bulb was higher wattage than tailight  bulb).  If fuse block diagrams on Internet are correct, Fuses 2 and 20 are suspect.

John