No, the dimmer does not control the LEDs. I was satisfied with the lighting just as it is. However, if your night vision is better than mine or possibly on a long night drive (which I avoid as I get more senior), you might wan't to be able to dim the dash lights. I have thoughts on how to do this but it would require more electronics.

An LED is essentially an ON-OFF device. You can control the light a small amount by controlling the current through the LED but this isn"t really enough control. The LED output can be controlled by turning it on and off rapidly and varying the duty cycle, i.e. the time the LED is pulsed compared to the time it is off. Much like setting the idle mixture control in my MB. If this is done fast enough, the eye doesn't see any flickering of the light.

I'm still waiting to see the interest in posting the pictures showing how I did this. We'll see.

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1986 300E
1993 Volvo 940 Wagon
1984 Volvo 240 (daughter's)
1976 Dodge 1/2T pickup, gas hog