Coolant Level Switch Ques.

[AW]

My low coolant level indicator keeps coming on despite the fact that the
coolant level is fine.  Coolant mix is fine, and light comes on when
start engine from cold.  I suspect it's the coolant level switch at the
bottom of the expansion tank.  In the archives, a lister suggested
testing the switch by unplugging it and watching for the indicator light
to go out.  If I do this, will coolant leak out from the bottom of the
expansion tank?  Car is 1990 80Q.  TIA for any help.
Andrew Wong
'90 80Q
'92 S4
'85.5 944