Rear Window Defroster; Tire Pressures & Wheel Alignment - RayTek Rayst25 Autopro User Manual

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Rear Window Defroster

Locating Broken Grid Lines
Rear window defroster uses heat through voltage
to defrost the rear window using metal strips
attached to the inside of the rear window. To
visually locate broken grid lines is difficult. To
trouble shoot defroster system grid lines turn
ignition on and activate rear window defroster.
Using the IR thermometer, measure temperature
across each defroster grid line from left to right
from inside of window. Temperature should
increase from left to right on grid line as
temperature is measured. If temperature remains
constant across grid line, check for a loose
ground for defroster grid. Temperature drops will
indicate location of broken grid lines. See Fig. 7.
If defroster does not turn on or temperature does
not increase, problem may be in voltage supply
circuit, relay or defroster switch. See appropriate
service information to diagnose and repair.
Fig. 7: Locating Broken Grid Lines
Tire Pressures & Wheel
Alignment
NOTE:
Before trouble shooting tire
pressures or alignment, ensure all tires are
properly inflated to manufacturer's
specification. Ensure tire size on vehicle is
the same across the front or rear and that
bias-ply and radial tires are not mixed.
16
Tire temperatures can tell you how well the tire is
using the tread surface and the road surface to
maintain control. The objective is to get the tire to
work effectively across the entire face of the tire.
This can be maximized for most vehicles by
adjusting tire pressures and alignment.
Tire Temperatures/Pressures
CAUTION:
Some vehicles are equipped with
tire pressure monitoring systems. If air
pressure is adjusted, system may set a
warning light. Check manufacturer's
information before adjusting air pressure
beyond factory specifications.
Optimum tire temperature should be little to no
temperature differential across the tire tread. On
a vehicle such as a taxi or a truck, this procedure
may not be suitable because of the varying loads
impressed upon the tires.
Tire manufacturers recommend tire temperature
differential for passenger car tires across the
tread should be less than 10°C (20°F).
Before test drive, ensure tires are properly
inflated to manufacturer's specifications.
To obtain an accurate temperature reading, test
drive vehicle in a low-traffic area, preferably on a
straight, level section of roadway. Operate
vehicle at a safe speed and bring to a complete
stop. Try to avoid any sharp turns or movements
during test drive. Stop vehicle, place in Park
(auto trans) or neutral (manual trans) and set
parking brake. Using the IR thermometer,
measure temperature at inside, center and
outside of tire tread surface. See Fig. 8.
Fig. 8: Measuring Tire Temperatures
1.888.475.5235