GE JVM1851 Owner's Manual page 28

Other features your model may have.
TURNTABLE
VENT FAN
VENT FAN
BOOST
SURFACE
LIGHT
28
Turntable
For best cooking results, leave the turntable on.
It can be turned off for large dishes. Press
TURNTABLE to turn the turntable on or off.
Sometimes the turntable can become too hot to touch.
Be careful touching the turntable during and after
cooking.
Vent Fan
The vent fan removes steam and other vapors from
surface cooking.
Press VENT FAN once for high fan speed, twice for
medium fan speed, a third time for low fan speed
or a fourth time to turn the fan off.
Press the VENT FAN BOOST pad for extra fan speed.
Automatic Fan
An automatic fan feature protects the microwave
from too much heat rising from the cooktop below it.
It automatically turns on if it senses too much heat.
If you have turned the fan on you may find that you
cannot turn it off. The fan will automatically turn
off when the internal parts are cool. It may stay on
for 30 minutes or more after the cooktop and
microwave controls are turned off.
Surface Light
Press SURFACE LIGHT once for bright light, twice for
the night light, or three times to turn the light off.