Heated Seat
Heated Seat
Description
The front passenger seat assembly contains critical components that affect the front passenger airbag deployment. Correctly functioning front passenger seat components are critical for the occupant classification system to properly classify the front passenger and calculate the proper airbag deployment. Unapproved modifications or service procedures to the front passenger seat assembly, its related components, or trim cover may inadvertently change the airbag deployment in case of a frontal crash. This could result in death or serious injury to the front seat passenger if the vehicle is involved in an accident. The following requirements must be strictly adhered to:
• Do not modify the front passenger seat assembly or components in any way.
• Do not modify the front seat center console or center position seat in any way.
• Do not use prior or future model year seat trim covers not designated for the specific model being repaired. Always use the correct seat trim cover specified for the vehicle.
• Do not replace the seat trim cover with an aftermarket trim cover.
• Do not add a secondary trim cover other than those approved by Volkswagen.
• At no time should any supplemental restraint system component or SRS related component or fastener be modified or replaced with any part except those which are approved by Volkswagen.
Vehicles with the heated seat option can be visually identified by the heated seat switches. Two heated seat switches (3) for the front seats are located in the center stack (4) rear heating, ventilation and air conditioning control unit (2). These two switches allow the driver and front seat passenger to select from two different levels of electrical seat heating (HI/LO). The front heated seat switches are an integral part of the HVAC control unit. If the switches are inoperative or damaged in any way the complete HVAC control unit must be replaced.
Vehicles with the rear heated seat option can be visually identified by the two heated seat switches (3) located in the sliding door trim panels (6). The sliding door trim panel mounted switches control the 2nd row heated seats. These switches allow the 2nd row seat passengers to select from two different levels of electrical seat heating (HI/LO). The 2nd row heated seat switches are available individually for service. If the switches are inoperative or damaged in any way they should be replaced. Refer to => [ Heated Seat Switch, Second Row ] Heated Seat Switch, Second Row.
The heated seat system for this vehicle includes the following major components:
• Heated Seat Element - Eight carbon fiber heated seat elements are used per vehicle, two for each heated seat. Two heated seat elements are integral to each seat, one in the seat back and the other in the seat cushion.
• Heated Seat Module - One heated seat module is used per vehicle. The heated seat module is mounted under the driver front seat. This module contains the control logic and software for the front and 2nd row heated seat system. The module communicates on the local interconnect network data bus.
• Front Heated Seat Switch - Two heated seat switches for the front seats are located in the center stack rear HVAC control unit. These two switches allow the driver and front seat passenger to select from two different levels of electrical seat heating (HI/LO).
• Rear Heated Seat Switch - Two heated seat switches for the rear seats are located in the sliding door trim panels (6). The sliding door trim panel mounted switches control the 2nd row heated seats. These switches allow the 2nd row seat passengers to select from two different levels of electrical seat heating (HI/LO). The 2nd row heated seat switches are hard wired to the rear door modules.
• Rear Door Module - A door module is concealed behind the trim panel of each sliding door. The rear door modules each utilize integrated circuitry and information carried on the controller area network data bus network. In regards to the 2nd row heated seat system, the modules communicate between the hard wired heated seat switches and the instrument cluster. The cluster then transfers the information to the heated seat module.
• Electromechanical instrument cluster, also known as the cab compartment node - The instrument cluster utilizes integrated software and information carried on the LIN and CAN data bus. The instrument cluster serves as the link between the heated seat switches and the heated seat module.
On vehicles equipped with heated cloth seats the heating elements are an integral part of the seat foam and cover. If the heating element is damaged or inoperative the complete seat cushion/cover or seat back/cover assembly must be replaced. Refer to => [ Seat Cover and Cushion ] Seat Cover and Cushion, or => [ Seat Back Cover and Cushion ] Seat Back Cover and Cushion.
For complete circuit diagrams, refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.
Operation
Front Seat Heated Seat System
The front heated seat system operates on battery current received through a fuse in the totally integrated power module. Fused ignition switch output circuits are used, so that the systems will only operate when the ignition switch is in the ON position. The heated seat system will turn off automatically whenever the ignition switch is turned to any position except On. If the ignition switch is turned to the OFF position while a heated seat is on, the heated seat will remain off after the engine is restarted until a front seat heated seat switch is depressed again. This prevents the vehicles battery from being drained by the heated seat system.
The heated seat switches for the front row seats are located in rear HVAC control assembly. The rear HVAC control is mounted in the lower portion of the instrument panel center stack. Amber LED's in the top portion of 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 once will select the highest level of heating. Pressing the switch a second time will select the lowest level of heating. Pressing the switch a third time will shut the heating elements off.
A heated seat module is used to control the heated seat system. The module is secured to a mounting bracket located under the driver front seat. The module responds to heated seat switch messages and ignition switch status inputs by controlling the 12 volt output to the seat heating elements through integral solid-state relays.
When either of the front heated seat switches are depressed a resistance signal is sent to the EMIC. The instrument cluster receives this message via the CAN data bus. The instrument cluster then sends a message via the LIN data bus to the heated seat module, signaling the module to energize the heating element for the selected seat.
The heated seat module energizes an integral solid-state relay, which supplies battery current to the heating elements. Heated seats turn off after one hour of continuous operation. If the highest level of heating is selected, the control system will remain at the high level for 30 minutes and then drop to the low level for 30 minutes. Then it will turn off. At that time, the number of illuminated LED's changes from two to one, indicating the change.
The module will automatically turn off the heating elements if it detects an OPEN or LOW short in the heating element circuit.
Second Row Heated Seat System
The 2nd row heated seat system operates on battery current received through a fuse in the TIPM. Fused ignition switch output circuits are used, so that the systems will only operate when the ignition switch is in the on position. The heated seat system will turn off automatically whenever the ignition switch is turned to any position except on. If the ignition switch is turned to the off position while a heated seat is on, the heated seat will remain off after the engine is restarted until a 2nd row seat heated seat switch is depressed again. This prevents the vehicles battery from being drained by the heated seat system.
The heated seat switches for the 2nd row seats are located in the sliding door trim panels near the door handles. Amber LED's in the top portion of each switch indicate the level of heat in use: Two LED's are illuminated for high, one for low, and none for off. Pressing the switch once will select the highest level of heating. Pressing the switch a second time will select the lowest level of heating. Pressing the switch a third time will shut the heating elements off.
The 2nd row heated seat system utilizes the same heated seat module as the front heated seat system. The module is secured to a mounting bracket located under the Driver front seat. The module responds to heated seat switch messages and ignition switch status inputs by controlling the 12 volt output to the seat heating elements through integral solid-state relays.
When either of the 2nd row heated seat switches are depressed a hard wired resistance signal is sent to the applicable rear door module (left or right). The applicable rear door module then sends a message via the CAN data bus network to the EMIC. The instrument cluster then sends a message via the LIN data bus to the heated seat module, signaling the module to energize the heating element for the selected seat. LED's in each switch indicate the level of heat in use. The switch LED's are controlled by the applicable rear door module.
The heated seat module energizes an integral solid state relay, which supplies battery current to the heating elements. Heated seats turn off after one hour of continuous operation. If the highest level of heating is selected, the control system will remain at the high level for 30 minutes and then drop to the low level for 30 minutes. Then it will turn off. At that time, the number of illuminated LED's changes from two to one, indicating the change.
The module will automatically turn off the heating elements if it detects an open or low short in the heating element circuit.