The backlighting, yeah the backlighting. Very simple solution. As easy as Ebay. Look for LED flexible peel and stick light strip. It does not need to be the weather resistant kind. That has a clear coating on it, and will not allow it to bend as tight inside the housing.
About $5 to $7 will get you a 5 meter strip. Thats approx 12 feet !!! The 5630 LED strip is the brightest dimmable i could find. It comes in many colors including red, orange, blue, light blue, purple green, pink, as well as white. i chose green though i wish there was a blueish green.
You line the perimeter of the gage housing with it. As far as electrifying it. No problem. There is a cut line every 3 light segments, along with positive and negative spots to solder wires onto it. It comes with a pair of black and red wires already soldered on one end.
I started peel and stick where a dash back lighting socket was located then worked my way around the perimeter of the gage housing allowing for enough space that i can cut the excess off at the cut line on the light strip. Being that the light strip is wired in parallel, the cut end does not need wires attached if they are attached at the other end of the strip.
I soldered the red and black wires to a gage bulb socket, and popped it back in place. This is where you want to hook up some test leads with a 9V battery and check to see if it lights up. LEDs are polarity sensitive. If they dont light up when testing with a negative case ground to the cluster housing with a fresh 9v battery, simply pop out the bulb socket and pop it back in reclocked 180° from the way it was. That will swap the wiring on the socket to allow a negative ground. Its shown lit up with a 9v battery in the pix. Its very efficient.
I also recommend swapping all the rest of the indicator lamps out with LEDs they make the other bayonet style as plug n play. This lessens the times you have to crack into your instrument cluster. Again remember LEDs are polarity sensitive
Heres pix
Hope this helps
Matt