Pug Dash/Schematic/digram symbols

If anyone is ever stuck on those cryptic dashboard symbols, ( like i was
with the water in diesel filter symbol ( after believeing the car was
telling me my casserole was ready lol )) take a look at this web site for
a complete list of all the symbols for all Pug models,

http://peugeot.mainspot.net/wiringall/symbols.shtml

Btw my car is the 505 GTD Estate "F"registration, and the dash has the
symbols and guage for Oil Level/Temperature, however the "level" light
never lights up, and the needle has a mind of its own, only moving when
the Glow Plug indicator is illuminated (moving into the red), then drops
when that goes out ?!?!?! sometimes it never bothers to move at all, does
anyone know exactly what this guage is telling me and how its supposed to
work at all ? also after some driving (about an hour or so constant) the
red "oil pressure" light starts to very faintly glow (only noticable at
night and also seems to be bringing on the STOP light and that illusive
Oil Level light like there all wired together !?! ) but never fully comes
on, whats that all about ?? Thanks peeps