There are two different headlight switches for Vanagon:
Early: # 251-941-531M
Late: # 251-941-531T
From the front they look and function identically. However, they are slightly but significantly different on the back. The early style switch has only 8 pins*, while the late style switch has 10 pins*.
Model Year Split Info:
• 1980-1988 the 8-pin switch ending in "M" was used
• 1989-90 the 8-pin "M" switch, or a "10" pin "T" switch is possible
• 1991 the 10-pin switch ending in "T" was used
*If you go by the model year to figure out which switch your Vanagon is wired for, you might get the wrong one. The only way to know exactly what you need is to pull the switch out and count the pins on the back.
Is it 8-pin (M) or 10-pin (T)?
Check out the related images above.