Heated seat not working. light gos on but no heat.

Are the connectors actually wired the same? Check the wiring diagrams for each seat if you can find them, otherwise trace the wiring from the internal components in the seat to the connector and make sure the heaters are going to heater power pins in the original harness, and temperature sensors are going to temperature sensor pins (temperature sensors may be polarized, that is, it makes a difference which pin goes to positive and which to ground).

The heated seats are a luxury feature that heat the front seats. This provides maximum comfort for the driver and the front passenger. To turn on the heated seats, press the heated seat button, which is a picture of a seat. There are two of these buttons, and each are located on the center console. The button on the driver's side of the console controls the heat for the driver's seat, while the button on the passenger's side of the center console controls the heat for the passenger's seat. Pressing the heated seat button will turn the heated-seats onto their highest setting. Pressing the button a second time will lower the heated seats to their medium setting. Pressing the button a third time will result in the lowest setting. Pressing the button a fourth time will turn off the heated seats. There are three lights next to the heated seat buttons to indicate what setting the heated seats are on.
Tip
The heated seats will only work when the engine is running.

could be that a separate fuse runs the element to heat the seat, or relay. try unplugging the connector under the seat and replug in to see if that fixes it. check for power at the feed side of the loom plug before you replug it to the seat .

Hi Jkelley, I'm glad to help!

After over 40 years in this business I've found that most, and I say most of the time when heated seats quit working its almost always the heated seat elements that go bad. J look and see if the switches light up when you turn the heated seats on. If they do that's is where I would start. If you remove the heated seat pad and its burnt then you know for sure that's the problem. Hope this helps and have an awesome day Jkelley.

Remove the ignition key. Unplug the HSM (heated seat module). It is under the passenger seat. You can easily accomplish this with the seat all the way back. Wait a few seconds they plug it back in. Start the engine. Turn the seats on. If the indicator lights come on for 2 seconds and then go out, further diagnostics is required. Hopefully they'll stay on and the seats will be working fine.

Thanks,
Ron

The following diagnosis might be helpful if the vehicle exhibits the symptom s described in this PI. Condition Concern Driver and passenger heated seats inoperative or shut off in 30 seconds. There will be DTCs B2435, B2440, B3606 and or B1825 set in the Drivers Seat Module. The adjustable pedal position sensor, seat recliner position sensor and both heat seat thermistors share the same 5 volt reference internal to the Drivers Seat Module. A fault in any of these components circuits can make the heated seats inoperative or shut off in 30 seconds, as well as, the seat recliner and/or adjustment pedals may move in short increments when operated. A fault in heated seats, adjustable pedal or seat recliner will affect BOTH heated seats. Note Even if the vehicle is not equipped with adjustable pedals DTC B3606 still may set.Recommendation/Instructions To help isolate the area of concern use the Tech 2 and go to Sensor Data in the Drivers Seat Module. Monitor the following parameters for being out of range Recline Position Normal range .39V 4.58V Pedal Position if equipped Normal range .39V 4.58V Psgr. Seat Heat Sensor- Normal range 1V-4V Drvr. Seat Heat Sensor Normal range 1V 4V If a parameter is found to be out of range inspect circuits for any opens, shorts to ground, or voltage. If none found replace the suspect component Please be aware of the following common areas of concern The adjustable pedal position sensor internally shorted pulling the 5 volt reference low. Disconnect the adjustable pedal position sensor and see if the heated seats start working correctly, if so replace.Note Important The APP accelerator Pedal Position sensor is NOT the adjustable pedal position sensor. Make sure the correct sensor, adjustable pedal position sensor, is disconnected.The seat recliner position sensor internally shorted pulling the 5 volt reference low. Disconnect the recliner position sensor and see if heated seats start working correctly, if so replace.An open in either heated seat thermistor circuits signal or low reference The most common is the passenger thermistor where it passes through seat connector C305 pin L or K or C399 pins R or G A chaff to ground on either heated seat thermistor signal circuits. The most common is circuit 5475 black red or dark blue shorted to ground in the passenger seat near the buckle.Note Important The heated seat thermistors act differently to OPENS and SHORTS than the adjustable pedal position sensor and seat recliner position sensor. The adjustable pedals and seat recliner sensors can be disconnected for testing of the heated seats. Where as the heated seat thermistor circuit must be working correctly before EITHER heated seat will operate. Disconnecting one thermistor, which may have a concern will not allow the opposite heated seat to work correctly, BOTH side must be operational before EITHER heated seat will perate.Clearing DTCs If DTCs will not clear when using the Tech 2 after a repair has been made, try operating the device in which the repair was made. Example, if a repair was made to the passenger heated seat thermistor circuit, the DTCs may not clear unless the passenger heated seat is operated.Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed GM bulletins are intended for use by professional technicians, NOT a do it urselfer. They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

The purpose of this bulletin is to provide the technician with the following service nformation Heated Seats Switch Operation Heated Seats Switch Diagnostics Heated Seats Switch Customer Information Switch Operation The engine must be running for the heated seat feature to work. The heated seats will shut off automatically when the ignition is turned off.Two buttons, located on the door, are used to control the heated seat. Press the orizontal (RH) button to heat the entire seat, back and cushion. Press the vertical (LH) button to heat ONLY the seat back.The three light bars are an indicator of the level of heat selected for either the entire seat (horizontal button) or ONLY the seat back (vertical button) To heat both the seat back and seat cushion at the same time, press the horizontal (RH) button with the heated seat symbol one time. All 3 light bars will glow indicating the HIGH temperature etting.The horizontal (RH) button does NOT have an ON FF indicator light.Press the button a second time, 2 light bars will glow indicating the MEDIUM temperature setting for the entire seat.Press the button a third time, 1 light bar will glow indicating the LOW temperature setting for the entire seat.Press the button a fourth time to turn the entire heated seat OFF.To heat ONLY the seat back, press the vertical (LH) button one time. An ON FF indicator light over the heated seat back symbol will glow to designate that ONLY the seat back is being heated.All 3 light bars over the horizontal (RH) button will glow indicating the HIGH temperature setting for ONLY the seat back.Press the button a second time, 2 light bars will glow indicating the MEDIUM temperature setting for ONLY the seat back.Press the button a third time, 1 light bar will glow indicating the LOW temperature setting for ONLY the seat back.Press the button a fourth time to turn the heated seat back OFF.Switch Diagnostics mportant: In order to eliminate unnecessary part replacement and comeback repairs, it is essential that the appropriate diagnostic tables and aids found in the applicable manuals are followed.Verify the condition prior to making any repairs. Refer to Seats and Seat Controls in the applicable Owners Manual or this bulletin for proper heated seat switch operation information.If an improperly operating front heated seat condition exists, refer to the Diagnostic Information and Procedures in the Seats sub-section of the applicable Service Manual in order to diagnose the system accurately.When measuring the resistance of the seat heater elements, ensure the values are within the updated range of 1.5-5.5 ohms. Refer to DTC B2425 or B2430-Clearing the DTC in the Diagnostic Information and Procedures in the Seats sub-section of the applicable Service Manual.Customer Information Some heated seat components from the above listed vehicles have been returned to the Warranty Parts Center (WPC) for heat function not operating properly. Analyses of these parts show 'no out of specification condition' or No Trouble Found (NTF)Provide customers with the knowledge that if bumped, either one of the heated seat switches can be activated/deactivated accidentally.Ensure customers have a thorough understanding of how the heated seat switches function.GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

Its generally the heating pad itself, located inside the seat. Quite often they burn out and melt the element. They have a coil of light gage wire routed thru a pad that is adhered to the seat in between cushion and cover. The wire breaks or heats up to where it opens the circuit and quits working. The light indicator is a separate circuit that just indicates to the driver the heated seats have been requested. t would be best to take to a dealer or maybe check out an upholstery shop for an estimate.

MORE THAN LIKELY THE HEATING ELEMENT HAS MALFUNTIONED. ITS A PRETTY COMMON PROBLEM IN HEATED SEATS

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.

check the fuse for the heated seats first then check the heating element to see if it is burned out