Automotive Electrical and Electronic Systems Classroom Manual Fifth Edition Update by John F. Kershaw

330 Chapter Fifteen
Figure 15-25. Typical power window control circuit.
(DaimlerChrysler Corporation)
one direction; current through the opposite winding
will make the motor turn in the opposite direction.
The motor armature is linked to the seat
mounting by a transmission that translates this
rotary motion into seat motion.
Ford and GM have made four-way power
seat systems that contain two reversible motor
armatures in one housing. Ford’s motors have
permanent-magnet fields, while GM’s motors
have series-connected electromagnetic fields.
One motor is linked to a transmission that
moves the seat forward and backward. The
other motor’s transmission tilts the front edge
of the seat. A single four-position switch controls
both motors. The switch contacts shift current
to different motor brushes (Ford) or to
different field windings (GM) to control motor
reversal.
Early GM six-way power seat systems use one
reversible motor that can be connected to one of
three transmissions. Transmission hookup is controlled
by three solenoids (Figure 15-27). The
control switch is similar to that used by Ford and
Chrysler, but the circuitry differs. Current must
flow through one of the solenoids to engage a
transmission, then through a relay to ground. The
relay points conduct current to the motor
brushes. Additional switch contacts conduct current
to the electromagnetic motor windings.
Chrysler, Ford, and late-model GM six-way
power seat systems use three reversible motor
Figure 15-26. A GM two-way power seat has a motor
with electromagnetic fields; current through the fields
determines the direction of the motor and thus the
movement of the seat. (GM Service and Parts Operations)
Figure 15-27. GM’s early six-way power seat systems
use one reversible motor that can be connected
to one of three transmissions. Transmission hookup is
controlled by three solenoids. (GM Service and Parts
Operations)