'I have a very dim "High beam" = indicator light.' 
 
I'm not sure if you have the same = problem but my bus (-88 1,6 TD) used to have dim HB light and finally it gets totally black.  I was sure the bulb has gone and try to supply + 12 V = directly to meter unit connector T14 pole 2 => the bulb hasn't gone and it is = really bright!
 
After few investigations I found the fault.  = The signal from high beam to the dash HB indicator light is got out from connector = C pole 17 (fuse box) and wired inside the fuse box to connector A pole = 28.  The fault was inside the fuse box (discontinuity).  I make jumper wire = (outside the fuse box) from C17 wire to A28 and since that my HB indicator light = has been working well.
 
Hope this helps,
 
Juha Koivisto
88 Vanagon (Caravelle) 1,6TD (old = school bus with 9 seats)
TURKU, FINLAND