The South African Grill uses H4 sockets (same as stock connector on the
80-85 Vanagon) for the main 7" round outer lights.  Jumper wires for high
beam and ground run to the smaller inner lights.

The 86-91 Vanagon uses 9004 sockets for the outer lights and a custom
connector for the inner lights (you can substitute 1/4" female disconnect
terminals for the stock inner light plug if you don't have the stock
wiring).  Remove the round white connector on the back of the inner lens by
turning it counterclockwise to determine which wire is the ground.

Both types of headlight sockets will be available at most good autoparts
stores, or can be found online if you can't source them locally.  If you
plan on running higher than stock wattage bulbs with either setup, high temp
ceramic headlight sockets are highly recommended.

With all model years, the headlight wiring color codes are as follows:

Yellow = Low Beam
White = High Beam
Brown = Ground

The pinouts for the headlight sockets can be found on my website here:
https://sites.google.com/site/vanagonheadlightrelays/helpful-information/lens-bulb-upgrades/headlight-socket-pinouts

Marine style butt connnectors (with built in heat shrink tubing) work well
for headlight connections, or you can solder and shrink wrap the wires if
you have a decent soldering skills and a good iron.

If you would like to avoid cutting any wires when installing your grill in a
different van, you can use one of my plug & play headlight conversion
harnesses:
https://sites.google.com/site/vanagonheadlightrelays/headlight-wiring-harnesses

Feedback on my products can be found here:
http://www.thesamba.com/vw/forum/viewtopic.php?t=377131&highlight=thatvwbusguy+comcast

Hope that helps,
Jay Brown
'85 Zetec Westfalia