This is a glow plug relay for the 20 second glow plugs. All of the new glow plugs that are available now are the 7 second type.
Quick Glow Plug and Relay Kit
Block Heater Kit for Diesel Vanagon
Glow Plug Relay for Diesel Vanagon 82-84 (quick) 7 second
Glow Plug (quick) 7 second