If you'll search on this site in this subject, you'll find a link to a pic of this low fuel light assembly. Best I can describe it is to say that it is a little smaller than 1" sqaure and has a bulb attached to a circuit board. The assembly will twist and rotate out from it's dash position from behind. I've found that these assemblys were present on about 25% of all of those era Rivs I found. HTH. A very nifty feature and will illuminate in bright orange when fuel is low. Direct bolt in for a TR.