DO NOT LET THE GLASS BALL , (LAMP) FOOL YOU, its really 2 lamps inside
infact just like the schematic shows, its exactly that way....
the question is.
1: is one booth low beams glowing dim?
2: or is one low beam glowing on on side and the high beam on the other.
as you may not know, kids wire in the wrong lamps. the mess this wiring all up./
does the red/white wire go to the seam exact pin 2 on both lamps? left and right.
if yes the its a dim issue, (voltage drop)
if not , the kid wired it wrong.
are both lamps stamped with the same bulb part number? (duh factor 1)
did the kid cut up the lamp flanges,
did the kid cut up the lamp socket so he could install the wrong lamps. or do so on one side, then not the other , then mis-indexed one side, kids are, well kids, tricks are for kids...
kid = junior grade PO(mad)
is this a DRL car.?
daylight running lamps. (on full time)
if yes, they have logic in the controller (many kinds in use) that flip the lamps funny with any brake failure, its a warning to NOT DRIVE cars with bad brakes.
IIRC the lamps INVERT , but not cross wise, that is impossible , save the nut KIDS.
ive had 2 cars with his funny logic.
got this weird stuff,,,, many hate it. and loves to melt connectors at the drop of hat too....
the are in parallel and were wired right day one.
both lamps can be aimed wrong
if one side is high beam and other is low, the lamps are wired wrong, or the bulbs indexed wrong (kids used a cutter on it)
of all that is ok. both beams same both sides all the time.
then its a dim issues.
wrong bulb (or bad (swap left to right) and dont allow gray silver coating inside, its End of life , marks.
dim is low low volts on 12v fuse side
or dim is too high volts on bulb ground pin, say over 0.5v is bad. (and industry bad ground spec)
if ground is too high work back to HL switch and find who is dropping too much voltage.