Question about 1994 Volvo 850

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Both front heated seats not working

Switches light up, main fuse ok but seats do not heat up

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  • Anonymous Jul 31, 2008

    both lights are coming on but not heating up

  • hue badna Oct 15, 2008

    the front passenger heated leather seat on my 94 volvo 850 turbo is not working. the light on the switch is working but there is no heat being produced. what can i do to correct this problem? i don't want to take it to the dealership beacause i know it can be costly. can you please let me how to fix it, thank you.

  • 02GF74 Oct 22, 2008

    LOL - same on my 1994 850. Don't buy the broken wire/seat moving theory as I have not moved the seats, or maybe a couple of times at most.



    I am thinking there is a fuse but not found it yet - didn;t see one in the main fuse box so there may be one in the harness to the seats.



  • Anonymous Feb 03, 2009

    Yep the same problem.. The driver seat only not heating.. on my 231,000miles 1996 850gt estate...

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Page 43 in the document linked to below is a wiring diagram of the heated seats in an 850. If you're lucky some wires have come loose and are hanging under the seats, if you're unlucky you might have to do some shredding of the seats in order to replace broken parts. If so there is a fairly inexpensive repair kit made specifically for this purpose, but I don't have the part number available right now. Arm yourself with a multimeter and get to it!

Good luck!

http://www.volvoclub.org.uk/tech/service/850/SystemWiringDiagrams.pdf

Posted on May 30, 2009

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Could be a broken wire on the bottom of the seats, the wires become hard over the years and the movement of the seat moving back and forth can cause the breakage.
It could also be the thermostats that are fitted into the base of the seats.

Posted on Jun 10, 2008

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Trying to find which fuse is for the heated seats on a 2004 ford explorer sports trak


Heated Seats
This system allows the electrical heating of the front seats on passenger demand.
The components of the system are:
  • the seat heating elements located in the seat cushion and backrest.
  • the heated seat control switch, located on the seat side trim panel.
  • temperature sensors located in the seat cushion heating elements.
  • heated seat relay.
Do both front seat heaters not work ? Do you know how to test electrical circuits with voltmeter ?
PINPOINT TEST J: THE HEATED SEAT IS INOPERATIVE Test Step Result / Action to Take J1 CHECK HEATED SEAT SWITCH OPERATION
  • Key in ON position.
  • Press the heated seat switch on the driver and passenger seats.
  • Are both heated seat switch indicators illuminated?
Yes
If both indicators illuminate, Go To Pinpoint Test K . If only one indicator illuminates, GO to J5 .

No
GO to J2 . J2 CHECK THE HEATED SEAT RELAY CIRCUITS
  • Key in OFF position.
  • Disconnect: Heated Seat Relay C3250 (located under the driver seat).
  • Key in ON position.
  • Measure the voltage at heated seat relay C3250-86, circuit 1003 (GY/YE), harness side and ground; and between C3250-30, circuit 566 (DG), harness and ground.
    s5r~tr~en~file=a0078817.gif~gen~ref.gif
  • Are the voltages greater than 10 volts?
Yes
GO to J3 .

No
REPAIR inoperative 1003 (GY/YE) or 566 (DG) circuit. TEST the system for normal operation. J3 CHECK HEATED SEAT RELAY GROUND CIRCUIT
  • Key in OFF position.
  • Measure the resistance between heated seat relay C3250-85, circuit 57 (BK), harness side and ground.
    s5r~tr~en~file=a0078818.gif~gen~ref.gif
  • Is the resistance less than 5 ohms?
Yes
GO to J4 .

No
REPAIR circuit 57 (BK). TEST the system for normal operation. J4 CHECK THE HEATED SEAT RELAY
  • Install a fused jumper lead between heated seat relay 3250-30, circuit 566 (DG), harness side and heated seat relay C3250-87, circuit 1064 (YE/LB), harness side.
    s5r~tr~en~file=a0078819.gif~gen~ref.gif
  • Do both heated seat indicators illuminate when pressed?
Yes
INSTALL a new heated seat relay. TEST the system for normal operation.

No
REPAIR circuit 1064 (YE/LB) to switches. TEST the system for normal operation. J5 CHECK INOPERATIVE HEATED SEAT SWITCH INPUT
  • Key in OFF position.
  • Disconnect: Heated Seat Switch C320 (Driver) or C321 (Passenger) for the inoperative heated seat.
  • Key in ON position.
  • Measure the voltage between heated seat switch C320-2 (driver) or C321-2 (passenger), circuit 1064 (YE/LB), harness side and ground .
    s5r~tr~en~file=a0078820.gif~gen~ref.gif
  • Is the voltage greater than 10 volts?
Yes
GO to J6 .

No
REPAIR circuit 1064 (YE/LB). TEST system for normal operation. J6 CHECK CIRCUIT 57 (BK) FOR AN OPEN
  • Measure the resistance between heated seat switch C320-4 (driver) or C321-4 (passenger), circuit 57 (BK), harness side and ground.
    s5r~tr~en~file=a0078821.gif~gen~ref.gif
  • Is the resistance less than 5 ohms?
Yes
INSTALL a new heated seat switch. TEST the system for normal operation.

No
REPAIR circuit 57 (BK). TEST the system for normal operation It's not that simple , being a fuse . It's probably the relay or the heating element .
PINPOINT TEST K: SEAT DOES NOT HEAT BUT THE HEATED SEAT INDICATOR ILLUMINATES WHEN PRESSED ? Does it ?
Your best bet would be to take to a qualified repair shop .
Do

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Heated seat not working on 2000 ford expedition eddie bauer


Check continuity on the seat heaters. If that's ok, check the grounds. Check power to the heaters while you are there.

Dec 01, 2013 | Ford Expedition Cars & Trucks

1 Answer

2002 Trailblazer heated seats won't work


First check circuit breaker #8 and fuse #19 in the rear fuse panel. If these are OK, you will have to troubleshoot the seat heaters themselves (loose connector, broken wires, defective heater coil, etc.)

Oct 13, 2012 | 2002 Chevrolet TrailBlazer

1 Answer

2005 Honda Pilot passenger heated seat does not work. Fuses are ok.


If fuse #3 20amp in the passanger under-dash box is good.
Check and see if the orange light for the high and low setting come on when you switch between high and low.
if light doesn't come on, the switch itself might be bad.
if light turn on for both setting then, it's a high chance it's the heat pads located under the seat cover need to be replace.

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1 Answer

2006 Buick Terraza drivers heated seat not working passanger side ok wiring seems ok


you will need to check the fuses first and if they are okay. then take a test light and check the switch for the power seat itself and see if you are getting power to and from the switch. if all is okay check power at connector for heated seat and if all is okay the heat is bad or it maybe the switch i have seen both. good luck

Dec 26, 2009 | 2006 Buick Terraza

2 Answers

The driver seat heater just quit. all fuses are good. how do you tell if the relay is good?


Swap it with a relay you know to be good and see if it works again,pick a relay that is not important to the function of your car.

Nov 01, 2009 | 2004 Cadillac SRX

1 Answer

Heated leather seats will not heat up. Switch lights up and all fuses are okay. Is there a hiddedn relay I am not finding? Is there a quick way to determine if the problem is in the heating element under...


are you saying neither the heated seat cushion nor heated seated back on either seat works? But the light or lights does work?

Please rate as solved if this helps you. It took some time to dig all this stuff up. Please report progress.

Here's some info to start you off:

  • The heated seat is inoperative — seat does not heat but the heated seat switch illuminates when pressed
  • Circuitry.
  • Heated seat module.
  • Seat heater and temperature sensor.
  • Seat back heater.
  • Heated seat switch.


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May 28, 2009 | 1999 Ford Expedition

1 Answer

2002 Grand Cherokee Heated Seats don't work


I will post it in 2 different posts because its too long DB

HEATED SEAT SYSTEM
Individually controlled driver and passenger side electrically heated front seats are available factoryinstalled optional equipment on this model, when it is also equipped with the power seat option. The heated seat system allows both the driver and the front seat passenger the option to select one of two seat heating ranges, Low or High, or to turn the individual seat heaters OFF using the heated seat switches located in the center lower bezel near the bottom of the instrument panel center stack. The heated seat switch circuit operates on ignition switched battery current supplied through a fuse in the junction block, only when the ignition switch is in the ON position.

The heated seat system consists of the following components
  • Heated seat elements
  • Heated seat sensors
  • Heated seat module (or memory heated seat module)
  • Heated seat switches.
The heated seat system also relies upon resources shared with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware, and component sensor current loads. At the same time, this system provides increased reliability enhanced diagnostics, and allows the addition of many new feature capabilities. For diagnosis of these electronic modules or of the PCI data bus network, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended.

The electronic modules that may affect heated seat system operation are as follows:
  • Body Control Module (BCM) - Refer to Body Control Module in Electronic Control Modules for more information.
  • Heated Seat Module (HSM) - Refer to Heated Seat Module in Electronic Control Modules for more information.
  • Memory Heated Seat Module (MHSM) - If the vehicle is equipped with the Memory System, refer to Memory Seat Module in Electronic Control Modules for more information.
Refer to Power Seats Premium I/III in the Contents of Wiring Diagrams for complete circuit diagrams. Following are general descriptions of the major components in the heated seat system.

The heated seat system will only operate when the ignition switch is in the ON position, and the surface temperature at the front seat heating element sensors is below the designed temperature set points of the system. The heated seat system will not operate in ambient temperatures greater than about 41 °C (105 °F) . The front seat heating elements and sensors are hard wired to the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM).

The heated seat switches are hard wired to the Body Control Module (BCM). The BCM monitors the heated seat switch inputs, then sends heated seat switch status messages to the HSM or MHSM over the Programmable Communications Interface (PCI) data bus. The HSM or MHSM contains the control logic for the heated seat system. The HSM or MHSM responds to the heated seat switch status messages, ignition switch status messages, and the front seat heating element sensor inputs by controlling the output to the front seat heating elements through integral solid-state relays.

When a seat heater is turned ON, the sensor located on the seat cushion electric heater element provides the HSM or MHSM with an input indicating the surface temperature of the seat cushion. If the surface temperature input is below the temperature set point for the selected Low or High heated seat switch position, the HSM or MHSM energizes the integral solid-state relay, which supplies battery current to the heating elements in the seat cushion and back. When the sensor input indicates the correct temperature set point has been achieved, the HSM or MHSM de-energizes the solid-state relay. The HSM or MHSM will continue to cycle the solid-state relay as needed to maintain the temperature set point.

The HSM or MHSM and the seat heater elements operate on non-switched battery current supplied through the power seat circuit breaker in the junction block. However, the HSM or MHSM will automatically turn OFF the heating elements if it detects an open or short in the sensor circuit, a short or open in the heating element circuit causing an excessive current draw, or when the ignition switch is turned to the OFF position.

See the owner's manual in the vehicle glove box for more information on the features, use and operation of the heated seat system.

I WILL POST THE REST

Jan 31, 2009 | 2002 Jeep Grand Cherokee

1 Answer

Heater seats dont work but light comes on.


Ok it is obvious since the light is coming on you are getting power to the switch. It could be a heated seat relay. Im fairly sure jeeps use a relay after the switch that is where I would start. Check and see if the Heated seat relay, and fuse are good

Dec 11, 2008 | 2001 Jeep Grand Cherokee

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