Hi Jim
I broke the first one I tried to take apart but it is actually easy. Take a look at the bottom of
http://www.canadianmilitarypattern.c...%20Harness.htm for some pictures of the switch taken apart.
Now as to how to disassemble here is a link to a short video I did today on a switch.
http://www.canadianmilitarypattern.c...n%20Switch.wmv hope this helps.
If anybody can not down load the video because of the speed of your connection let me know and I'll drop the file size.
As to the add on oil gauge I'll bet it was because they did have the replacement gauge for the instrument cluster.
Cheers Phil