Honda 1997 Odyssey Owner's Manual page 177

Lights
VERTICAL ANGLE GAUGE
5. Check the vertical angle gauge.
The bubble should be centered
underneath the longest scribe
mark on the gauge.
Maintenance
HORIZONTAL ADJUSTMENT
6. If either indicator is not aligned
with its "0" mark as described, an
adjustment can be made using a
Phillips-head screwdriver to
realign it with the "0" mark. Please
refer to the illustrations.
VERTICAL ADJUSTMENT
7. If you cannot get an indicator to
align, have your Honda dealer
inspect the car for body damage or
suspension problems.