To really get to the bottom of this you must use a voltmeter. The relays
are primarily intended to remove the current of the headlights from the
headlight switch and ignition switch. These switches burn out from long
use and if brighter bulbs are fitted these switches will burn out
sooner. The relays prevent this. At the same time the relays will boost
the voltage to the bulbs by giving the current a shorter path, but other
weaknesses along the wiring path can still reduce headlight output from
what it once was and should be. A voltmeter should be used to compare
the voltage reading at the alternator, the battery, the fuse panel, and
the headlight connector. This measurement comparison should be done with
the engine running, high beams on and the heater fan on speed 2.

Mark

Mark A Kippert wrote:
> As far as I know, the source feeding the relays is correct. The relays are plugged into the specified male blades on the back of the fuse block (as directed in the instructions).
>
> I guess what would really help is to understand why headlights that must have worked fine when the van rolled off the assembly line, now work so poorly.
>
> Not sure what you mean by "any wiring upgrade needs to include improving the current path from the alternator, not just the battery." I'm guessing the lights are fed by the battery, so the relays are improving this path. Here on the list, relay kits are typically recommended as the fix for poor headlight output, as well as many Vanagon sites. I don't recall reading that the current from the alternator should be improved as well (of course I've only been on the list about a year).
>
> Mark K
> 1986 GL/2WD/4SPD
>