Have a look at this post from the Samba. Scroll down a bit, and you'll find
a table that someone composed with the original bulbs, as well as what to
use if you're looking for something a little brighter. It lists what will
fit, as well as the brightness and wattage. As noted, just be careful about
using anything which might get too hot.

http://www.thesamba.com/vw/forum/viewtopic.php?t=388197&highlight=wiki+lights

Ed
--------------------------------------------------
From: "Trev" <gneiss9@GMAIL.COM>
Sent: Monday, September 05, 2011 12:51 PM
To: <vanagon@GERRY.VANAGON.COM>
Subject:      Front bulb type for signal/parking, '91 GL

> I've got two different bulbs on my front signals/parking lights. What is
> the proper bulb designation for a '91 Vanagon GL?
>
> Thanks,
> Trevor Reynolds
> "ShinkanSEN"
>
>
> Sent from my Motorola DynaTAC Car Phone.
>
> Fahrvergnugen!