So this kinda goes with the hidden gauges thread, but I didn't want to totally hijack it -

Several pickups, several different combinations of aftermarket gauges/tachs/etc. I can change bulbs to get the colors close enough, but what about intensity? Most recent one is an older farm pickup with stock bulbs in the dash and a new cheapie Amazon tach, with LED lighting. It's BRIGHT! - too bright, and the regular dash dimmer doesn't really dim it. I suppose I should go full LED on the dash bulbs first, and probably will, but they aren't THAT much brighter. So the ultimate fix is to dim the tach down to match the rest of the dash, regardless how it's set up, just so that it matches. I'm thinking something along the lines of this -

https://www.ebay.com/itm/Universal-1...sAAOSwa2lZfYT9

wired inline from the instrument panel circuit to the tach light, so I can basically 1-time "adjust" it and get it to match. Once that's done, though, I wonder if I could get a measurement off it, then replace it with the correct resistor and move it along to the next one? What's everybody else's solution to this??

 

I guess the LEDs in the tach are hard wired to its circuit board? Dunno if you want to open it and check, but maybe it actually uses 194 LEDs which can be switched out for incandescents. You could also open it up and put something over the LEDs to 'muffle' the light output some.
If you're hellbent on dimming it, you could completely cover or even remove the LEDs, and somehow mount an incandescent 194 in there.