Mercury Sable 1999 - Manual (Page 142)

Do not let the reservoir for the master
cylinder run dry. This may cause the brakes
to fail.
WINDSHIELD WASHER FLUID
Checking and adding washer fluid
Check the washer fluid
whenever you stop for
fuel. The reservoir is
highlighted with a
symbol.
If the level is low, add
enough fluid to fill the
reservoir. In very cold
weather, do not fill the
reservoir all the way.
Do not put engine coolant in the container
for the windshield washer fluid.
Checking and adding washer fluid for the
liftgate (if equipped)
The opening for the reservoir is located on the
passenger side under the tail lamp. Refill this
reservoir with the same fluid you use for your
windshield.
Maintenance and care
142