So… nothing is as it appears.
While dismantling this silly gauge… when I got spanner ring finally off and pulled out… the bulb was lit and lying behind the guages. Now the funny part. While reassembling the guages, AC block etc, I turn on lights. The Volt meter was dark. I then fished around and found it had fallen out. argh. A little kapton tape i could reinstall it by finding blind hole. I then assembled it… guess what happened… yes, the temp guage (3rd guage) was dark. Bulb was still in place. I pulled light from gauge… changed bulb around back of AC dial block still installed and then reinstalled new bulb.
Moral… you don’t need to totally remove gauge to fix bulb or assume it’s burned out.
When blindly installing the recrangular socket into dial, it is horizontal when locking into dial back.
Now where is that wrist guard?