LEDs dont really illuminate like normal bulbs, they tend to project in a straight line. hence not working well for lighting up gauges, youll probably get a series of dots for gauge illumination instead of a glow
Hoosierbuddy, myself and others have attenpted this. The bottom line is that LED technology has not yet gotten to the point where the LEDs can project the same candlepower as an incandescent bulb of the same size (physically).
Phil spent some time performing physical tests backing the statement above up.
I recently have researched a supplier's website (LEDtronics.com) that also confirms this...
One way to clean things up is to get a really good ground and wiring system checked out... That most likely will make a difference....
I had LEDs before with white faced gauges and they were better than stock but still pretty dim. As said above, LEDs tend to project in a straight line but you can get inverse LEDs that project to the side.
Last year I removed those and replaced them with electro-luminescent gauges that are much, much better.
Go to www.servicelighting.com. Buy yourself a bunch of 5 watt (.37 AMP) 13.5 volt Wedge Base #590 Miniature Light Bulbs. These are twice as bright as the stock 194 bulbs. You are increasing the amps from 0.27 to 0.37, so there will be some increase in heat. The avg livetime is 2000 hours, reduced from the 2500 hr lifetime of the stock 194s, but still a long time. I paid $1.95 per bulb. The increased brightness is substantially better. Would I like them brighter? Sure, but I'll take what I can get. I have not tried also taking off the blue diffusers and replacing with the blue caps that someone else suggested, but that would probably make them even better. While they may be hotter, I have not melted my own gauge cluster with them, but your mileage may vary.