Sprinter 3500 V6-3.0L DSL Turbo VIN 45 (2007)
Seat Heater: Description and Operation
Heated Seats
Description
DESCRIPTION
Vehicles with the heated seat option can be visually identified by the two heated seat switches located in the instrument panel switch pod (also known as
the center console switch unit or Switch Bank Module/SBM) (1). The instrument panel switch pod is located just below the heater and air conditioner
controls in the center bezel (2) of the instrument panel. Each heated seat switch (4) has two Light-Emitting Diode (LED) indicator lamps, which indicate
the selected level (Low or High) of the seat heater. Pressing the switch button up or down initiates a heated seat cycle. Heat remains on until switched off
or until the ignition is turned off. If switched off by the ignition, a switch button must again be pressed to restart seat heating. The heated seat system
allows the driver and front seat passenger to select from two different levels of electrical seat heating (HI/LO). The heated seat system for this vehicle
includes the following major components:
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Heated Seat Switch - Two heated seat switches are used per vehicle, including two Light-Emitting Diode (LED) indicator lamps for heat level
indication. The two heated seat switches are located in the instrument panel switch pod. The instrument panel switch pod contains the solid state
electronic control and diagnostic logic circuitry for the heated seat system. The individual switches in the instrument panel switch pod cannot be
repaired and are not serviced individually. If any component within the switch pod is inoperative or damaged, the entire switch pod unit must be
replaced.
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Heated Seat Elements - Four heated seat elements are used per vehicle, one for each front seat back and one for each front seat cushion. The
elements are integral to the individual front seat and seat back cushions and cannot be removed from the cushions, once installed at the factory.
Hard wired circuitry connects the heated seat system components to each other through the electrical system of the vehicle. Refer to the appropriate
wiring information for complete circuit schematic or connector pin-out information. The wiring information includes wiring diagrams, proper wire
and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness
connectors, splices and grounds.
Operation
OPERATION
Rocker type heated seat switches located in the instrument panel switch pod (also known as the center console switch unit or Switch Bank Module/SBM)
(1) operate the heated seat system. The instrument panel switch pod receives battery current through a fused ignition switch output (run) circuit when the
ignition switch is in the On position. The instrument panel switch pod responds to heated seat switch button input and ignition switch status inputs by
controlling the 12v output to the front seat heating elements through integral solid-state relays.
When either of the heated seat switch buttons are depressed the heating element for the selected seat is energized. Amber Light Emitting Diodes (LEDS)
on the each switch indicate the level of heat in use: two LEDs are illuminated for high, one for low, and none for off. Pressing the switch button
downward will select high-level heating. Pressing the button upward will select low-level heating. Pressing the button a second time in the same direction
will shut the heating elements off.
The heated seat switch energizes an integral solid-state relay in the instrument panel switch pod, which supplies battery current to the heating elements.
When high-temperature heating is selected, the switch pod provides full battery current to the seat elements. When low-temperature heating is selected,
the switch pod provides pulsed battery current to the seat elements at a rate of 33 percent on time. The control system will automatically switch to the
low-temperature heating after approximately five minutes. At that time, the number of illuminated LEDs changes from two to one, indicating the
change. Operation on the low-temperature setting will continue indefinitely until the switch button is pushed to turn the system off.
