# Heated Seat Problem....



## carbon02 (Feb 25, 2011)

Guessing it's a problem with the resistance of the heating pads in the seat. The heated seat pads talk to the heated seat control module under the drivers seat, with controls at the HVAC dash. 

Unzip the back of the seats near the bottom, disconnect the pads, and check the resistance. That might be something to try. I've got some info in my heated seats thread in my signature.


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## brian v (Dec 25, 2011)

What ever there is in the power circuit that sends a signal to turn on this particular circuit is staying in a closed loop for some reason ..
As carbon has addressed you need to troubleshoot the circuit mentioned .
Take voltage readings in the wiring at the seat and proceed from there ...

Dude this will be an exhaustive endeaver and I would have to research the seat circuits in more detail to give you a procedure of how to find the likely electrical fault ...

Remember this a closed circuit and has live volts and amps .

May just be a user error !


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## Daisy81 (Jun 17, 2012)

I doubt it is user error. I had the same problem three times. Once on the drivers seat and the other on the back rest of the drivers seat. The third time I no longer cared which one was burning out because I realized what was going on and I read the GM the riot act.

If either has a fault the whole thing won't work.

My dealer tried to tell me it won't be covered again except for a one year warranty. I told them that this has been a ongoing problem for the life of the vehicle. If they don't continue to fix it I will file a grievance with Chevy themselves against the dealer and if that doesn't work take them to small claims.

It's amazing that after the third time in three years after throwing my fit with the general manager at the dealership that I didn't have the issue again last winter.

There is a design flaw and rather then fix the issue the dealers prefer to slap in a new element and let that one burn out over time because it is easier and makes them money.


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## NickD (Dec 10, 2011)

Here is the circuit diagram:

But this will have to wait until they fix this board, won't let us post photos.

A 30 amp fuse powers both seats. if one seat is working other should work too.

Heater temperature and blower heated seat controls are just door bell type push button switches that fire commands to the Seat heating control module that controls both seats, actually four heating elements two are in series for each seat. Control module is GM part # 13502042, can look this up on the net, runs around 60 bucks. Its located at the very front of the drivers seat bottom.

Heating elements are not cheap at 100 bucks each, times four, Just a piece of nichrome heating wire, with others break open the stitching, find where this long wire is broken, use a special solder to repair it and sew it up again.

It amazes me, can go to any store, buy a 120VAC heating pad, with a line cord, controller with three different settings, the heating element, and the pad for ten bucks, sure getting screwed by the car manufacturers. Four such heating pads will cost you 40 bucks, for the Cruze for essentially the same thing, looking at 500 bucks. 12 volts requires a lot less nichrome wire.

Only other element is a heat sensor that feeds back to the control module. Sure it just a simple thermostat, but can't seem to find it in the parts list. As usual, the shop manual does not show the resistance of the heater elements, but have another seat to compare that with.

Control module also has to be programmed, here is the procedure.

"
*Heated Seat Control Module Programming and Setup* 

The seat heating control module must be programmed with the proper calibration software. The module stores and utilizes this information however if it is not properly configured with the correct calibration software, the seat heating control module will not control all of the vehicle features properly.

Ensure that the following conditions exist in order to prepare for seat heating control module programming:




The battery is fully charged.
The MDI data link connectors are secure.
The scan tool is loaded with the most current software version.
All disconnected modules and devices are reconnected securely.
This entire procedure has been reviewed before proceeding.
Do not reprogram the seat heating control module unless directed by a service procedure or a service bulletin.

*Seat Heating Control Module Programming* 

To program and setup an existing or new replacement seat heating control module, perform the following procedure: 




Access the Service Programming System (SPS) and follow the on-screen instructions. Refer to Service Programming System (SPS) See: Testing and Inspection\Programming and Relearning\Service Programming System (SPS).
On the SPS Supported Controllers screen, select HVSMF Front Seat Heating Control Module - Programming and follow the on-screen instructions.
If the HVSMF Front Seat Heating Control Module fails to accept the program, verify all scan tool and seat heating control module connections are secure.

*Note:* After programming is completed, perform the following to avoid future misdiagnosis:




Turn the ignition OFF for 10 seconds.
Open and close the door.
Connect the scan tool to the data link connector.
Ignition ON, engine OFF.
Clear all DTCs from all modules."

Wife wanted electrically heated seats with our 2LT and was the only option we elected to purchase for a 1,000 bucks, also included leather, better radio, better suspension, and the spare tire and a jack. Considered this to be a bargain.

Tell her to use a very gentle touch on that climate control module, some guy here hit it too hard, can't just replace that switch, have to buy the entire control module for $$$$$$.


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## brian v (Dec 25, 2011)

So IT is Exhaustive ....


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## NickD (Dec 10, 2011)

Still can't post a photo yet for the circuit diagram.



Ah, copy and paste worked. Sure that component between pins 2 and 3 is some kind of a thermistor or heat sensor, telling the controller how to regulate the voltage to the heating elements depending on what setting you have.

Ironically showing two of these sensors on the passenger side, but the second one is not used, is this a spare? Is it even there? Two of my kids with Chrysler T&C's had to have their heating elements replaced, fortunately before their BB warranty was still in effect. 

Another area I had problems with nichrome wire was in resistive blower motor speed controls, especially in the lowest speed mode. Two ways of doing this for a certain resistance, use a very thin wire and not very many turns of it, using a larger gauge wire, requires a lot more turns. They prefer the cheapest way, but if your motor stalls just a little bit like when its darn cold outside, that thin wire will turn red hot and break.

Get around this by using a much heavier gauge wire and more turns, as long as it will fit, no sense in laying out cash for a new one, same problem.

Maybe they are doing the same thing with these heated seats. Anything to save a couple of cents, but sure does not reflect in what they want for these things with super outrageous prices.

Never know until I look. All I have to know is the total resistance of the element, nichrome wire is rated at resistance per foot, just divide the total resistance by the resistance per foot, tells you how many feet you need.

Whoops forget about that circuit, text is too long.


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## NickD (Dec 10, 2011)

View attachment 195530


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## brian v (Dec 25, 2011)

Hay Nick what do you think is in that heated seat control module ?


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## NickD (Dec 10, 2011)

Apparently a 89 cent microcontroller with flash ram in it, has to be programmed and can lose code. Can also buy them with your code burnt into it. With a heat sensor, must have an A to D converter, have these too. 

Are they using point contact relays for switching? Or is that their symbol for a much cheaper power MOSFET transistor?

A90 is a resistor circuit for multiplexing two or more signals into one wire, would also be sharing that AD to converter, does save a couple of wires. 

First microprocessor was designed by Motorola, a one bit job around 1970, around about ten years later, added some peripheral circuits to it to perform like a small computer. First ones has separate memory where one could copy the code and save it and even burn a replacement. Have on of these, gathering dust.

Use to be in inline circuit packages anywhere from 18 up to 60 pins, also history, using so-called beam lead construction on, tiny dots on the bottom of the chip that can be directly mounted to a surface mount PC board. For protection, cover it with expoxy, impossible to replace a bad chip, so the entire PC board and the housing its located in is throwaway. Since they are dedicated to a specific operation, can charge any price for it as they desire. 

Ran across a bad one in a Hi Fi amplifier with code burnt into it, Amplifier new cost 190 bucks, they wanted 165 bucks just for the chip. Not worth repairing.


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## NickD (Dec 10, 2011)

See the price of the climate control panel with electrically heater seats came down, now 85 bucks.












 Manufacturer: GM
 Part Number: 95146203
 Part: HEATER CONTROL
 Part Notes: NEW, W/AUTO TEMP CNTRL, W/HEATED SEATS
PARTS: Order by description.
 


 Sale Price: $84.48

Best web price with free shipping I can find is $95.63.

Not sure if these are membrane or micro switches, but guessing the latter. Long time ago ordered a pack of 50 of these switches, very common in remotes, garage or vehicle, and in game controllers. But I see my drawer is empty, time to order some more. Can replace these quicker than I can find and order a new remote, and the most common problem is these switches, and a heck of a lot cheaper.










In lots of 50, about a dime each.


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## joshuab (Apr 16, 2014)

I had a similar issue w/ my heated seat. I would turn on the button & the 3 levels would light up & then about a min later I would see the lights go off, took it to the dealer under warranty at the time & found out it was the heated seat element went bad & they had to replace it.


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## NickD (Dec 10, 2011)

Sounds like they are using a timing routine in the program, waiting for a response from that heat sensor, if they don't get it, shut the darn thing off. Ha, took a course on programming microcontrollers way back then, even aced it, but found writing code was extremely boring.

Had to memorize mnemonics and were different for each controller. Kind of recall, also a 15 minute timer on these things, wonder if mine still work, haven't used them in a couple of years. Was nice when I hurt my back a couple of years ago. Willing to bet, using the smallest gauge nichrome wire, 90 bucks for these pads is outrageous.


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## NickD (Dec 10, 2011)

See my electrically heated seats are still working, notice the passenger air bag light also goes on when you switch on the empty passenger seat, even though nobody was sitting in there. Also not wearing the seat belt warning alarm came on.


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## Chevy Customer Care (Oct 29, 2011)

NickD said:


> See my electrically heated seats are still working, notice the passenger air bag light also goes on when you switch on the empty passenger seat, even though nobody was sitting in there. Also not wearing the seat belt warning alarm came on.


I am sorry to hear this, NickD. I recognize that it can be frustrating to have the air bag light appear when there is not a passenger seated on your Cruze. If you are interested in taking your vehicle to Chevrolet dealership, feel free to send us a private message. We would be glad to assist you!

Best,

Cristina Y
Chevrolet Customer Care


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## NickD (Dec 10, 2011)

Chevy Customer Care said:


> I am sorry to hear this, NickD. I recognize that it can be frustrating to have the air bag light appear when there is not a passenger seated on your Cruze. If you are interested in taking your vehicle to Chevrolet dealership, feel free to send us a private message. We would be glad to assist you!
> 
> Best,
> 
> ...



Ha, thank you, but no thank you, none of my GM dealers around here know nothing about electronics or electrical.

Besides, this was just a test and do have two ways to turn it off. One way is to put in a 20 pound turkey in that seat, safety belt on of course. Ha, may even cook it, but may take awhile.

Other way since no one was sitting there, was just to switch it off, was just pointing out how it does work. So after I did run my test to make sure it was still working and getting warn, just switched it off.


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## NickD (Dec 10, 2011)

Oh, and even with that electrically heated switch turn if, if you put in a 20 pound turkey, a box, or anything that weighs 20 pounds or more, will have to listen to that alarm. That pressure switch under the seat fabric does not know the difference between a human, a turkey, a box, or anything that weighs over 20 pounds.

Only way to keep it off is to attach the safety belt, for a turkey?

What else doesn't know the difference? How about the O2 sensor? Doesn't know if a cylinder is misfiring or if the engine is running lean, with the former, thinks the engine is running lean so enriches the mixture that will shortly burn up your catalytic converter that will even cost you a lot more $$$$$ to repair than just replacing a spark plug.

Yet another is that traction control, it doesn't know you are in a skid, all it knows is if one wheel is spinning faster than the other, so thinks you are in a skid and kills the engine. Not very bright either when driving when one wheel hits a patch of ice.

Should hire some engineers that still know how to think.


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## Chevy Customer Care (Oct 29, 2011)

NickD said:


> Ha, thank you, but no thank you, none of my GM dealers around here know nothing about electronics or electrical.
> 
> Besides, this was just a test and do have two ways to turn it off. One way is to put in a 20 pound turkey in that seat, safety belt on of course. Ha, may even cook it, but may take awhile.
> 
> Other way since no one was sitting there, was just to switch it off, was just pointing out how it does work. So after I did run my test to make sure it was still working and getting warn, just switched it off.




I am Sorry to hear this NickD. If you do change your mind in the future, you can always send us a private message. 

Best,

Cristina Y
Chevrolet Customer Care


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## morrislex (Feb 21, 2017)

I have a 2017 - Gen2 - Cruze LT. Drivers seat heat stay on all the time - low - regardless what you have set on console on/off button. Is this module under the seat ?


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## kayleyteal (Nov 27, 2020)

Has anyone who has replaced their seat at home to fix this needed to bring it into the dealer after for programming? I had my passenger seat replaced last year (airbag not turning on) by a friend and the seat needed to be programmed by the dealership before it would work again, hoping if I try to fix the driver side heated seat I wouldnt have the same problem (as its 150$ each time)


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## carbon02 (Feb 25, 2011)

If you replace just the heated seat element that's attached to the foam pad under the seat cover you shouldn't need any programming. Is it the drivers side seat or back that's burned out? You should be able to unzip the seat cover and access the heated seat element wires at the bottom of the seat, Check resistance with an Multimeter. If it's open resistance infinity then the element is burned out


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