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Question moved to model category.
Check the connections to the module and the element. There is help in the forums and videos as well, although not all on the Ford Flex, the idea is the same.
JustAnswerhttps://www.justanswer.com > Ford Repair
Jan 24, 2019 - If the resistance reading of step 2 shows proper value, perform an amperage draw test of the heater elements by applying power to the YE/BU wire ...
Heated Seat System Operation
The driver and passenger heated seats have 2 heat zone operating modes with 3 heat level modes and will operate only while the engine is running. The heat zones are determined by which of the 2 heated seat buttons are pressed, while the heat level is determined by the number of times they are pressed. Pressing the seat cushion button 1 time will activate the seat back and cushion heater elements in the high mode. Each time the seat cushion button is pressed the seat back and cushion heat level is reduced from high to medium, low, and off. Pressing the heated seat back button 1 time will activate only the seat back heater element in the high mode. Each time the seat back button is pressed the seat back heat level is reduced from high to medium, low, and off. During heated seat operation the heat zone operating mode may be changed without affecting the current heat level mode.
The heated seat switches are momentary contact switches and are inputs to the driver and passenger door modules. Battery voltage is supplied to the switch assembly from the door module, and when a heated seat switch is pressed and released a brief switch signal voltage is supplied to the door module. Whenever the door module receives an active heated seat switch input, the next heated seat operating mode is determined by whatever the current mode may be. The seat heater elements are controlled by the driver seat module using inputs from the door modules through Class 2 serial data circuit messages. The driver seat module controls the voltage supply and the ground circuits to the seat heater elements. When a heated seat function is commanded active, the seat module will switch battery voltage to the heater element supply circuits, and ground is provided through low side drive control circuits. During heated seat operation both the seat back and cushion heater elements are supplied battery voltage. The seat module grounds the appropriate control circuits for back only or back and cushion heating modes, and opens or closes the active control circuits as necessary in order to maintain the desired seat temperature. The seat module relies on inputs from thermistors located in the driver and passenger seat backs to control heated seat temperatures. The thermistors are 2 wire sensors supplied with a 5-volt referenced signal circuit and a low reference circuit from the seat module. Resistance through the thermistors varies with temperature causing the heated seat sensor signal circuit voltage levels to decrease as the seat back temperatures rise. The seat modules allow heated seat operation only while the engine is running which is determined by a Class 2 serial data circuit message from the powertrain control module.
Heated Seat Components
The heated seat system consists of the following components:
• Driver and passenger heated seat switches
• Driver and passenger seat back heater elements
• Driver and passenger seat cushion heater elements
• Driver and passenger seat back temperature sensors
• Driver seat module
• Driver door module
• Passenger door module
Do you know what B - body DTC -diagnostic trouble code are ?
DTC B2425 Driver Seat Heater Circuit
DTC B2435 Driver Seat Back Heater Sensor Circuit
DTC B3941 Front Seat Heaters Circuit
Heated Seat Always On
Step
Action
Yes
No
Schematic Reference: Driver Seat Schematics and Passenger Seat Schematics
Connector End View Reference: Power Seat Connector End Views
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Operate the heated seat system.
Does the system operate normally?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
Go to Step 3
3
Install a scan tool.
Display the Heated Seat Status parameter in the driver seat module Input/Output data list.
Start the engine.
Does the scan tool display the Heated Seat Status parameter as Off?
Go to Step 6
Go to Step 4
4
Display the Heated Seat Mode parameter in the door module Inputs data list.
Does the scan tool display the Heated Seat Mode parameter as OFF?
Go to Step 6
Go to Step 5
5
Turn OFF the ignition.
Disconnect the heated seat switch connector to the door module.
Start the engine.
Does the scan tool display the Heated Seat Mode parameter as OFF?
Go to Step 7
Go to Step 8
6
Replace the driver seat module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Is the repair complete?
Go to Step 9
--
7
Replace the heated seat switch. Refer to Front Seat Heater Switch Replacement .
Is the repair complete?
Go to Step 9
--
8
Replace the door module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Is the repair complete?
Go to Step 9
--
9
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
Go to Step 3
your best bet , have a qualified repair shop diagnose the problem
Looking at a wiring diagram for the passenger seat an checking wiring colors mite help you figure it out . But then again maybe not . Electronic's involved here , Right door module .
Heated Seat Components
The heated seats consist of the following components:
• Left heated seat switch
• Right heated seat switch
• Memory seat module
• Left door module
• Right door module
• Left seat cushion heating element
• Left seat back heating element
• Left seat cushion temperature sensor
• Right seat cushion heating element
• Right seat back heating element
• Right seat cushion temperature sensor
Modes of Operation
The heated seat module (MSM) controls heated seat operation for both the driver and passenger seats. There are 2 modes of operation available for heated seats; both the seat cushion and seat back heat, or seat back only heat. When a heated seat temperature signal request is received, the MSM will activate both the seat cushion and seat back heating elements. When the heated seat BACK ONLY mode button is pressed once the MSM will deactivate the seat cushion heating element and leave the seat back heating element ON.
Heated Seat Switch/LED Indicators and System Operation
The left and right heated seats are controlled by separate heated seat switches located in the door panels. Ground is supplied to the heated seat switches through the switch low reference circuits from their respective door modules. The door modules also control the heated seat switch heat mode and temperature indicators. The memory seat module (MSM) controls the heated seat operation for both, the left and right heated seats.
The following describes the sequence of operation and how the MSM responds to each of the switch inputs.
• High Temperature--When the heated seat switch is pressed once, ground is applied through the switch contacts and the switch signal circuit to the door module indicating the high heat request. In response to this signal, the door module applies a low current voltage through the 3 temperature indicator control circuits illuminating all 3 LEDs indicating the high temperature mode. The module then sends a message via the GMLAN serial data line to the MSM indicating the heated seat request. The MSM then applies battery voltage through the heating element supply voltage circuit to the seat cushion and seat back heating elements. At the same time, it supplies a ground through the element low reference circuits to the seat heating elements.
• Medium Temperature--When the switch is pressed a second time, the MSM sets the temperature level to medium heat. The door module removes the voltage from the high temperature indicator leaving 2 LEDs illuminated indicating the medium temperature mode.
• Low Temperature--When the switch is pressed a third time, the MSM sets the temperature level to low heat. The door module removes the voltage from the medium temperature indicator leaving 1 LED illuminated indicating the low temperature mode.
• System OFF State--When the switch is pressed a fourth time, the MSM removes the battery voltage and grounds from the heating elements. The door module removes the voltage from the low temperature indicator, indicating the system OFF state.
• Back Only Mode-When the heated seat is ON and the BACK ONLY mode button is pressed, ground is applied through the switch contacts and the heated seat back only mode signal circuit to the door module. In response to this signal, the door module sends a GMLAN message to the MSM indicating the back only mode request. The MSM then opens the ground path to the seat cushion heater element, leaving the seat back heater active. The door module turns OFF the seat cushion/back mode indicator, then applies a low current voltage through the heated seat back only mode indicator control circuit illuminating the back only mode indicator.
Know how to test an what test is the key to finding the problem .Not guessing . The connector you found may or may not have anything to do with it . What color are the wires ? I have factory service repair manual . Does it have memory seats ?
The Memory Seat System consists of the following components:
• Memory seat module (MSM)
• Seat horizontal motor
• Seat front vertical motor
• Seat rear vertical motor
• Seat recline motor
• Lumbar horizontal motor
• Seat horizontal position sensor
• Seat front vertical position sensor
• Seat rear vertical position sensor
• Seat recline position sensor
• Lumbar horizontal positional sensor
• Seat adjuster switch
• Seat lumbar switch
• Memory seat switch
• PWR SEATS Circuit Breaker 30 A
• MEMORY RPA Fuse 7.5 A
The following checks and repairs can help you:
1. In the fuse box within the bonnet - check fuse number 22, if burnt, replace it
2. Check fuse 19 in the fuse box inside the car located under the dashboard on the driverside
3. If these steps don't help, the problem may be with the wiring and connection between the module and the seat cushion - inspect it
4. Check if the signal return on the circuit is adequately functioning - if the module is being informed of an active seat
5. If there is a problem - repair or replace the circuit and/or wiring.
you have elements underneath the seat cover most likely the drivers bottom seat element is burned out, you can check the resistance of it with a on ohm meter there is a 2 wire connector that goes to the backrest and then a 2 wire connector that goes to the seat cushion, more likely its the seat bottom that is burnt out
The first where the seat does not seem to heat, with the light staying on, I would think this to be a broken wire in the heating mat. The F-150 seat bottom is usually where this happens, right where the thigh would be on the seat. To test, on the heated seat module under the seat, the Yellow w/ Light Blue stripe wire goes to the seat bottom then to the Gray w/ Light Blue stripe wire to the seat back and then back to the Violet w/ Light Blue stripe wire to the heated seat module ( the bottom and back are in series ). Unplug the connector, and with a meter set to resistance or ohms, 1st check the Yellow w/ Light Blue stripe wire to the Violet w/ light blue stripe wire. You should read a high resistance ( if it is a scale, you need to use the 1K or 10K ohm or scale range ). You should get a very high resistance. If you read an open, there is a broken wire some where. 2nd check the Yellow w/ Light Blue stripe wire to the Gray w/ Light Blue stripe wire. If you have an open on the seat bottom and seat back, chances are this will also show an open. If it reads as an open, you need to replace the heated seat mat that is open. When you take the seat cover off, it will be obvious where the problem is at. You can also consider a new seat bottom at the same time, if you are going to the trouble of removing the seat cover.
The seat not getting very hot could be a break down in the element or the temperature sensor ( also in the seat bottom ). The cure for this is to replace the seat bottom heated seat mat. IF it is the temp probe, this will have an impact on the seat bottom and back temperatures.
Over time I have noticed that the seats work a little less every year. Hard to tell until you get a new element for them how bad it is. The elements are MSRP $ 60.00, Ford dealer selling parts online : ~ 40.00 + S/H. The cushion is ~ MSRP 120.00 online price ~ 80.00. The cushion is not required, as long as you are careful removing the old element. I usually replace the cushion if I am going to the trouble to remove the seat cover, specifically on the driver's side. With a new seat cushion, the truck will feel new again .
Here is a heated seat TSB for cars built prior to 12/14/07
TSB 09-4-8 03/09/09 INOPERATIVE HEATED SEAT(S) - BUILT BEFORE 12/14/2007
FORD: 2005-2007 Five Hundred, Freestyle 2008 Taurus X, Taurus
MERCURY: 2005-2007 Montego 2008 Sable
ISSUE Some
2005-2007 Freestyle, Five Hundred, Montego and 2008 Taurus, Sable and
Taurus X vehicles built before 12/14/2007 may exhibit an inoperative
heated seat(s). This concern may be caused by an intermittent open
element in the heated seat mat.
ACTION Follow the Service Procedure steps to correct the condition.
SERVICE PROCEDURE The
heated seat system is controlled by the heated seat module located
underneath the front passenger seat cushion. The heated seat switches
are part of the heating ventilation air conditioning (HVAC) module but
the heated seat system operates independently from the climate control
system. The heated seat module regulates seat temperature by monitoring
resistance of a thermistor type thermostat located in the cushion heater
mat. The heated seat module is designed to remain on, heating the seat
and maintaining temperature until switched off. For vehicles built
before 5/1/2006, the module will time-out and switch off after 10
minutes.
1. Refer to Workshop Manual (WSM), Section 501-10 for pin point test on inoperative heated seat(s). a.
When testing the heater mats resistance and circuits for an
intermittent open, technicians should sit in the seat while testing the
circuit resistance, move the seat in multiple seating positions and
apply pressure to several areas of the heated seat mat to ensure the mat
element is not open intermittently.
2. Refer to WSM 501-10 for heated seat element replacement when an open electrical circuit has been identified.
Parts Block WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage IMPORTANT
: Warranty coverage limits/policies are not altered by a TSB. Warranty
coverage limits are determined by the identified causal part.
OPERATION DESCRIPTION TIME MT090408 Use SLTS Operations If Actual Available Or Labor Time Performed As Actual Time
DEALER CODING CONDITION BASIC PART NO. CODE 14D696 28
Most likely an open circuit in one of the elements in the seat cushion or seat back.
You can check them with an ohm meter. The plugs will be under the seat near the inside seat hindge. The cushion will come in on the YE/LB wire and leave on the GY/LB,then this wire will feed the seat back element and come back to the module on the VT/LB wire. If you have an open circuit in either one then neither will work since one feeds the other. You can get the element seperate but the seat cover or back will have to be removed to replace.
It is usually the seat cushion element that goes bad.
You should be able to move the seat forward to get to the wiring harness. The way the system works is power comes from heated seat module to the lower cushion on the WH/BU wire goes thru the element in the cushion and then comes out on the BU/WH wire and then goes thru the element in the seat back then out on WH/RD wire back to module. If it has an open circuit then no heat from either on cushion or seat back. You can check them with an ohm meter. Usually it is the element in the cushion that goes bad. You can get the element seperately but cover has to be removed to replace it.
Most likely one of the heater elements in either the seat cushion or seat back is open.It leaves the module and goes to the seat back on the YE/LB wire thru the seat back and leaves there on the GY/LB wire and goes to the seat cushion and leaves there on the VT/LB. An open in either one of these will cause it not to work.Usally its the seat cushion one that goes bad.
You can test them with an ohm meter and you can get the heated element seperate. Just have to remove the cover to replace it.
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