If you put in a relay kit that means you spliced wires along the way. I have had many issues with spliced wires getting OLD and LOOSE in my Van (Subaru conversion). I would CHECK all splices and solder them if you haven't done so already as a step in troubleshooting.
Could be bad grounds as well. I would inspect the high beam switch on the column too. I assume you mean the headlight switch at the dash when you mention its 1 yr old.
 Sean G

      From: Dan N <dn92610@GMAIL.COM>
 To: vanagon@GERRY.VANAGON.COM 
 Sent: Friday, January 27, 2017 10:19 AM
 Subject: headlights problems
   
hi all,

on my 1988 tintop vanagon... recently when I turn on the headlights, these
symptoms appear:

- headlights are dim
- high beams are on at the same time as low beam  - on low beam setting at
the turn signal switch

note: headlight switch is new a year ago - headlight relay kit..

could it be:

- grounds?
- turn signal switch?

anything else to look for?

thanks for any help

dan