Can the back light color in the gauge be changed without a electronic display

ck on line they do offer colored back grounds in somecases

Yes, they sell the bulb replacements at digitaldash.com, an ebay vendor. You will have to remove the cluster to access the bulbs on the rear. Twist the bulbs out and install the new custom color leds bulbs in their place. Pretty cool, we just modified a GMC Tahoe here at Precision Tune Auto Care in Decatur.