Why is one meter brighter than the other?

OK, so my meter lights were out and I decided to upgrade to the superbright 1.5W white LED bulbs. Both meters illuminate, the left one (speedo) is dimmer than the right, but actually looks more like what I would expect. The right one (tach) is brighter but also seems to have two bright spots top and bottom where the bulbs are located.

Anybody else see this phenomenon?

All lights are illuminating, I checked all four new bulbs before installing.

crappy ground on the dim one
def a ground fault/semi short
PS
WHY is it always the ground that rots?
I think its cause the ground is a negative and may attract salts or other oxidizers that are positive?
anyone?

Maybe, but the odds are against it. The LEDs draw so little current that a marginal connection wouldn't cause any appreciable voltage loss.

The funny thing is, the dim meter looks more like what I would have expected and the brighter one looks way too bright compared to "normal". hard to see in the photo because of the reflected light from the headlight but the left meter actually looks normal. The right meter's brightness is about the same except for the really bright spots top and bottom where the bulbs are.

I wonder if it's just the bulbs. The wiring should be all parellel, so same volts should be on all 4 bulbs. I'd try swapping the brights with the dims and see if the problem moves to the opposite guage. My guess is chinese bulbs quality or lack of.

RonKZ650 wrote: I wonder if it's just the bulbs. The wiring should be all parellel, so same volts should be on all 4 bulbs. I'd try swapping the brights with the dims and see if the problem moves to the opposite guage. My guess is chinese bulbs quality or lack of.

Not Chinese bulbs, top quality made in USA (see below).

I tested them all before I put them in, all very bright and all the same.

I wonder if there is just a difference in the plastic diffusers inside the meter. These are 30 year old meters and plastic turns yellow over time. The "dim" meter has two separate bulbs fed by different lines so it's unlikely it's the wiring. On that meter, both bulbs look the same. It's just the bright side that looks like it has "spotlights" top and bottom where the bulbs are. Actually looks kind of odd, like the lights are so bright they are going through the meter face.

Are the tube's good inside the dim gauge ?
If the tube's are bad or missing the light will be spread inside the gauge and not get aim'd at the gauge face..