guage light is dim on heat indicator caterpillar 257b?

Answer 1

Sounds like the gauge mount is not making good contact, ie not a good ground for the light.

Try pulling the instrument block foward, remove that guage an clean the metal where it slide in and clean the metal on the mount. pull bulb out of socket and clean bulb and socket.

Spray WD-40 on all that clean metal. Should take care of that one dim bulb.