Coolant Level Light 91 200 TqM 10v

[hayes myers]

Coolant Level Light came on... coolant was below the minimum line, however
had not moved much in a while. (seemed stable). i added fluid today (close
to a litre) and the light stayed on.  What could cause this? Perhaps the
resevoir? Mine is faded yellow.. perhaps the float switch is messed up.  HOw
would I check that?  I was a little worried with the light...but now figure
it is just a case of an electrical gremlin.  Give me a shake if I'm wrong on
that account.

Thanks!
Hayes

oh yeah: 91 200 TqM 10v