DIY: Heated Seat Troubleshooting & Replacement

[stimpy2301]

Summary: This DIY will walk you through a method to test your heated seat, and how to replace the driver’s side lower cushion only. While I was prepared to do both the lower seat cushion (hereafter referred to as “cushion”) and the upper backrest cushion (hereafter referred to as “backrest”), my troubleshooting determined only the lower (seat) cushion pad was faulty. As such, I replaced only the cushion and NOT the backrest. Someone who has a faulty backrest heating pad will have to add to this DIY later … though I suspect most problems will be the result of the cushion.

Things you should know:

-- The problem with my heated seat was similar to those described LATER (around p. 6) in this thread -- where I hit the switch, the light stays on for anywhere from 30 seconds to a few minutes, then shuts off, and the seats never get hot.

-- If the Troubleshooting Method ‘A’ yields inconclusive results (as mine did), then you’ll need replacement parts for BOTH the cushion AND backrest to complete Troubleshooting Method ‘B’.

-- Part numbers for driver’s side cushion & backrest with heating pads (in my 2012 LTZ; verify your parts first!) are 95919161 (backrest) & 95019557 (cushion). From gmpartsdirect, including shipping, cost will be $136.50. I hope one of you will be kind enough to buy the backrest from me instead, since I didn’t need it, and will lose $20 (restocking fee) if I return it. If we start a chain of passing these parts around, this will help us all out – just like this online family deserves!

-- GM does not sell the heating pads by themselves – you have to buy entire new foam cushions along with them (you order them with or without heat). This is really stupid, IMO – there’s no reason they couldn’t sell the pad (which is a thin fabric with embedded heating wire, with adhesive on one side to stick to the foam) with a simple peel-away label covering the adhesive. (That’s how I received them for installation on my previous car, so I know it can be done.)

-- I was able to complete the cushion R&R without removing the entire seat from the vehicle, so this DIY does not contain instructions to remove the entire seat.

-- I typically deal with spacecraft & aircraft in my day job, so here’s a refresher on orientation & descriptive terminology (and abbreviations) I may be using as I write this:
Fwd = forward, toward the nose of the vehicle
Aft = toward the tail of the vehicle
Port = left
Stbd = starboard, right
Inbd = inboard, toward the port/stbd centerline (middle) of the vehicle
Otbd = outboard, away from the port/stbd centerline (middle) of the vehicle
Obviously, all references to up/down/above/below will be with respect to the distance from the ground.

Reminder: I am calling the upper backrest foam cushion the “backrest” and the lower seat foam cushion the “cushion”.

Finally, a DISCLAIMER:
-- By attempting this DIY, you accept all responsibility for your actions, so do so at your own risk. If you’re not comfortable with taking responsibility, then feel free to go pay your dealership $521 to do this for you. I am in no way liable for anything that happens to you and your car. Know that, if you have leather, performing this work will age it – you’ll inevitably end up with some new wrinkles. Also note, I do not know what differences there may be in working this process with cloth interior, or with the passenger seat, or with a different trim (e.g., RS). My vehicle is a 2012 LTZ.

Before & after – you can see some new wrinkles in my leather.

Bill of Materials & Tools

-- Multimeter (for Troubleshooting Method A)
-- Mirror (optional but helpful)
-- 10mm wrench (for disconnecting battery)
-- Driver and/or ratcheting wrench with a Torx (star) T25 size bit
-- Small/thin flathead screwdriver
-- Needlenose pliers or hog-ring removal pliers
-- Hog ring pliers (*)
-- Hog rings (optional, can re-use existing ones)
-- GM Part # 95919161 (backrest)
-- GM Part # 95019557 (cushion)
(*) Trust me, just buy these. I found the ones you see in the photo for ~$11 at Home Depot in the chain-link fence section, as none of the local auto parts stores had them in stock. I’ve dealt with automotive upholstery a few times before – and while removing hog rings with needlenose pliers is easy enough to not need the removal tool, reinstallation is a PitA without the proper tool. So save yourself time and aggravation and buy this.

See next post for Troubleshooting Methods A & B, and the post after that for Cushion R&R.

 

[stimpy2301]

Troubleshooting Method A

This simple method involves gaining access to the heating pads’ wire connectors, which you can test with a multimeter to determine if you’ve had a catastrophic failure (e.g., broken or burnt-through wire).

1) Move driver’s seat as far forward as possible, to maximize access from the back seat.

NOTE: Use caution when using a droplight (shown in my photos) – with standard bulbs, those get crazy hot and could burn yourself or your interior. I use a CFL in mine.

2) The upholstery on the aft side of the backrest has (2) clips (pulling the fabric tight) beneath the seat. Look under the seat (from the floor area in the back seat) and release these (2) clips by pulling them slightly forward.

3) With this fabric loose, lift it up and locate two wire bundles connected with white connectors. This is the connection from the cushion heating pad to the backrest heating pad. The ‘male’ end is for the backrest pad; I will call this Connector Z. The ‘female’ end is from the cushion pad; I will call this Connector Y.

4) Although you’ve released the backrest fabric, there is more fabric visible. This is part of the cushion fabric. It attached beneath the seat in the same manner as the backrest fabric – but with (4) clips this time. Locate and release all (4) clips by pulling them slightly forward.

5) With this fabric loose, lift it up and locate two more wire bundles connected with white connectors. This is the connection from the car’s power to the cushion heating pad. The ‘male’ end is for the cushion pad; I will call this Connector X. The ‘female’ end is from the car’s power; I’ll call this connector W.

Next we will test the heating pads for continuity. In other words, we’re going to verify the wires are not broken or burned out. If we check the resistance of the wiring and come back with zero resistance, this means the wire is intact. If we come back with infinite resistance (shown as ‘1’ on the multimeter) then the wire is broken and replacement is required.

6) Disconnect connectors Y & Z.

7) With your multimeter set to resistance (Ohms), touch one probe to each prong in connector Z. Multimeter should respond and read 0.00 (or some very small number, 0.0x). If it reads 0, your backrest heating pad wire is intact. If it reads 1, your backrest heating pad has a broken wire and should be replaced.

8) Disconnect connectors W & X. Reference the figure below for prong identification.

9) With your multimeter set to resistance (Ohms), touch one probe to Prong 1 in Connector X, and the other probe to Prong A in Connector Y. Multimeter should respond and read 0.00 (or some very small number, 0.0x).

10) With your multimeter set to resistance (Ohms), touch one probe to Prong 4 in Connector X, and the other probe to Prong B in Connector Y. Multimeter should respond and read 0.00 (or some very small number, 0.0x).

If the multimeter returned zeros in the previous two steps, then the wires for your cushion heating pad wires are intact. If either returned a ‘1’, then your cushion heating pad has a broken wire and should be replaced.

11) One additional test should be performed – verify you have power running through the pad. (Just because the wire isn’t intact doesn’t mean it’s getting power!) Reconnect connectors W & X, but leave Y & Z disconnected. Start the car, and turn on the heated seat. (Time is limited – without Y & Z connected, it will shut off after a short time, just like the original problem!) Using the multimeter (and verifying the heated seat light is still on), check the voltage between the prongs in connector Y. Should read ~14V. This indicates you have proper power coming from the cushion pad wire out to the backrest pad wire.

(I suppose you could perform this same test between prongs 1 & 4 on Connector X too, to verify the car is sending power to the cushion pad, but I neglected to do this.)

-- END OF TROUBLESHOOTING METHOD A –


NOTE: Aggravatingly, my cushion & backrest passed Troubleshooting Method A. This means the wires were intact and power supply was good, but there was still something wrong – since the car kept shutting the heating elements off. Perhaps a wire was loose? Perhaps frayed / partially broken and couldn’t carry sustained load? Hard to say. This means the next step is Troubleshooting Method B.

Troubleshooting Method B

BOTH replacement parts (cushion & backrest) are required. This method will help us determine which element(s) are causing the problem, and will save us time, trouble, and $$ by not replacing components that are still good.
Since you have access to all the wiring in the back seat, bring the new backrest & cushion into the back seat area with you.

1) We already know: Old Cushion + Old Backrest = Fail. Disconnect all connectors (W & X and Y & Z).

2) Connect new cushion’s Connector X to car Connector W. Hook up new backrest connector Z to new cushion’s Connector Y. (In other words, you’ve connected the entire new set of pads to the car power.

3) Start car, turn on heated seat; verify new pads get hot, and stay on (without premature shutoff like the old ones). Assuming they do, we’ve now proven New Cushion + New Backrest = Pass.

4) Shut off car.

5) Disconnect connectors Y & Z. Connect old backrest Connector Z to new cushion Connector Y.

6) Start car, turn on heated seat and see what happens – does the old backrest now get hot and the system doesn’t shut down prematurely? Or does it still shut down?

IF New Cushion + Old Backrest = Pass, then we can conclude there is a problem with the Old Cushion.

IF New Cushion + Old Backrest = Fail, then we can conclude there is a problem with the Old Backrest, and will need to further test the Old Cushion.

7) Shut off car and disconnect all connectors (W & X and Y & Z).

8) Connect old cushion’s Connector X to car Connector W. Hook up new backrest connector Z to old cushion’s Connector Y.

9) Start car, turn on heated seat and see what happens – does the old cushion now get hot and the system doesn’t shut down prematurely? Or does it still shut down?

IF Old Cushion + New Backrest = Pass, then we can conclude there is a problem with the Old Backrest.

IF Old Cushion + New Backrest = Fail, then we can conclude there is a problem with the Old Cushion.

10) Shut off car and disconnect all connectors.

You should now know which parts are causing problems – old cushion, old backrest, or both. In my case, it was only the old cushion. When you think about it, it wouldn’t surprise me if most of the problems were the result of a problem in the cushion, because the cushion and its wires are going to see more forces applied to it – your full weight on it every time you get in & out (vs, just leaning against the backrest), and every time you shift your weight around on the cushion.

So, since only my cushion was bad, I proceeded to replace the cushion only. See the next post for Cushion Replacement.

 

[stimpy2301]

Cushion Replacement

NOTE: Slide the seat fwd & aft on its track as required for ideal access during this procedure.

1) Using 10mm tooling (wrench, socket, etc.), disconnect your battery. This is a precautionary measure – your seat is equipped with airbags, wires, etc. Though probably unnecessary, better safe than sorry.

2) Remove height adjustment lever as follows:

2a) Using thin flathead screwdriver, pop the round face off the height adjustment lever on the otbd side, revealing (2) attaching screws. (Note, my photo shows I popped the face off the recliner lever too; this is not necessary.)

2b) Remove the (2) screws (using T25 torx bit) attaching the height adjustment lever, then remove the lever itself. CAUTION! These screws are very short so be ready to catch them!

3) Next, loosen up the otbd plastic as follows. Complete removal is not required (and not possible with recliner lever still in place.)

3a) Remove (1) T25 screw located in a recess on the otbd side of the plastic, beneath the footprint of the (removed) height adjustment lever.

3b) Remove (1) T25 screw located on the inbd side of the plastic, at its fwd end. Note, the plastic has a ‘lip’ here that you’ll have to pull fwd to clear the metal frame during removal.

3c) On the inbd side of the plastic, under the seat, push in the tab on the large plastic ‘plug’ securing it to the metal seat frame. Push the plug otbd through the hole in the frame.

3d) Plastic should now be free to flex away from the seat as shown in the photo.

4) Release the upholstery clips around the otbd & inbd sides of the cushion, by pulling the fabric down. Note, you can leave the fwd clips attached if desired, for easier reinstallation. To remove the inbd clips (along the center console), I found slightly better access for my hand with the seat slid all the way forward on its track.

5) (If you’ve performed the troubleshooting already, you can skip this step – you’ve already done it). Unclip (2) clips coming down from the backrest upholstery’s aft fabric, underneath the seat (accessible from backseat floor). Unclip the (4) clips from the cushion’s upholstery, also underneath the seat.

6) Now that you’ve released all the perimeter fabric clips from the inbd, otbd, & aft sides of the cushion, reach between the cushion and backrest (from the front) and start pulling the upholstery out toward the front. Also, pull out the cushion heating pad wires from between the cushion & backrest.

7) Tricky part: the cushion upholstery has a strap near the aft end that ‘hugs’ the foam from top to bottom, around the inbd/otbd sides. It’s connected beneath the seat with Velcro, but I found the Velcro very tight and mostly inaccessible due to seat frame hardware. Reach beneath the seat (from the backseat floor) and work/pull this strap in the aft direction. Then, return to the front of the seat, reach between the cushion & backrest, and ‘squish’ the cushion foam until you can pull this over the foam and up to the top.

8) Hog Ring Time! There are (10) hog rings holding the upholstery to the cushion, located as shown. Undo them from aft-forward using hog ring removal pliers or needlenose pliers, revealing the cushion foam & heating pad as you go.

Tip on hog ring removal using needlenose pliers:

Grab one side of the ring with your needle-nose pliers, and twist the pliers. This will create a gap in the ring ends.

Then, simply turn the ring so the gap is parallel to the metal underwire, so you can pull the underwire through it. Remove the ring by hand for reuse later on the new cushion.

Upholstery removal:

9) Once you’ve detached all (10) hog rings, the cushion foam should be completely loose – there’s nothing else holding it in place. Simply pick it up and remove it.

NOTE: At this point, I considered peeling the old heating pad off the old cushion, and peeling the new heating pad off the new cushion. However, it’s adhered pretty well in some places, and I broke the wire on the old pad during the attempted removal. (Perhaps this part of the wire was already partially broken, and this was the cause of my problem? Not sure. Besides this, I hadn’t noticed any visible defects.) So, considering the cushion is loose, I just swapped the whole cushion (foam & all) rather than risk damaging the new heating pad.

10) If you don’t have new hog rings, then remove the hog rings from the old cushion. Grip them with pliers and open them up more in preparation for reinstallation with the hog ring pliers.

11) Starting from the fwd inbd location, reattach the upholstery to the new cushion with (8) of the (10) hog rings. Do not install the aft-most (2) yet. (If you’ve never used hog ring pliers: put the hog ring in the plier jaws so you can hold it in the pliers with one hand. The ring should be shaped like a ‘C’ with the opening pointed out of the plier jaws. Feed the upholstery ‘underwire’ into the ring, then push the pliers down over the cushion foam’s underwire. When both underwires are in the ring, squeeze the pliers to clamp the hog ring around them.)

12) Remember that annoying strap from Step 7? Do that next. Push the strap aft between the cushion & backrest; squish the cushion as required to feed it over the foam and underneath. Move to the backseat floor area, and continue feeding the strap until it’s down below the cushion foam.

13) The cushion foam may have bunched up a little during the last step; reseat it accordingly, and feed the heating element wires between the cushion & backrest.

14) Reattach the upholstery with the remaining aft (2) hog rings.

15) This might be a good time to verify everything still works. Connect connectors W & X, and Y & Z. Reconnect your battery. Start the car. Turn on the heated seats and verify everything’s all good. Shut off the car when you’re done, and disconnect the battery again if you’d prefer.

16) Reconnect the upholstery clips along the inbd & otbd perimeter. They’re tricky, you have to pull them down, then rotate/flip them 180-degrees (up/down) before they’ll clip on. Hard to explain, but some trial & error will show you.

17) Backseat floor, under the seat: Reconnect W & X (if you haven’t already) and pull the aft edge of the cushion upholstery down to reattach its (4) clips under the seat. Position the wire bundle with connector Y protruding aft between the 3rd & 4th clips (the two inbd-most), to ensure it can’t get pinched in the seat track.

18) Reconnect Y & Z, and pull the aft edge of the backrest upholstery down to reattach its (2) clips under the seat.

-- END OF CUSHION REPLACEMENT –-

And there you have it! The return of toasty goodness!

Obviously, if your backrest was the problem – and not the cushion – then YOU’LL have to add to my DIY with yours.

Remember, you’ll need both components from Troubleshooting Method B to figure out which element(s) are bad. As such, anyone who’s going to attempt this DIY next (as a thanks for writing this DIY) please buy the backrest from me instead of GMPartsDirect so I can recoup some of my $. (I’ll have to get a shipping quote in the meantime … if I’m going to lose more than $20 overall, I may as well just return it to GMPD and eat the restocking fee, lol). Pending shipping quote, I’ll send it your way for $65 shipped to help you save a few bucks too. (It will cost $68.15 shipped from GMPartsDirect.) You’ll still need to order the cushion from them, also for $68.15 shipped. This way I can at least recoup some of my funds.

Best of luck … I’ll do my best to answer any questions you may have. Went out for a drive yesterday after completing the job … ahhhh so toasty...

 

[Fry]

As a heated seats user, I really appreciate this guide. It's one of the best guides I've seen written on the forums.

The pictures are clear, the arrows highlight steps, and the guide also warns of pitfalls. Thank you very much for writing it. I hope I never have to use it!

 

[Natesriv]

Wow

 

[Eric Smit]

very good write up.

 

[sbelljr]

My newly replaced (extended warranty) heated pads aren't getting nearly as hot as the old ones / the originals in my passenger side seat. They used to get very hot, like the HIGH setting on most other cars, but now it is just barely enough to notice on a cold day.

Have you noticed a difference in heating output (perhaps a revision to avoid breaking them like they have been?), or did my local dealer screw up?


Also- it may be possible to test the pads better with a 12v power supply. I assume the BCM for the heated pads is turning them off after 60s due to under/over current. If someone could test the current for good pads, we could compare that value to other, possibly broken pads to help determine failure.

Careful not to melt a faulty pad though. That would be bad!

 

[Papasonic]

Stimpy 2301
An awesome professionally done do-it-yourself thread! I'm impressed; thank you for the time and effort to prepare this.

 

[stimpy2301]

Have you noticed a difference in heating output (perhaps a revision to avoid breaking them like they have been?), or did my local dealer screw up?

No, temperature-wise, it still gets as toasty as I remember.

 

[sbelljr]

No, temperature-wise, it still gets as toasty as I remember.

Hmm. Maybe I should take it back to the dealer then... It's sufficient heat for about 55F, any colder and it's hardly any better than nothing.

 

[mja]

Will the heated seat foam from the leatherette LTZ fit the LT cloth seats?

I'm in the process of reupholstering the front/back seats with a leather/suede custom job and am looking to see if anyone knows if the foam between trim models is interchangeable/swappable.. basically are the seat frames the same?

I'd like to upgrade the heated seats in a stock fashion if possible, rather than going with aftermarket seat heaters.

 

[mja]

A tip for the install job - to decrease the amount of wrinkles in your vinyl/leather. Take the entire seat out. get a cheap steamer or rent one, and steam your foam as you reinstall the upholstery. Should see less wrinkling of the seating surface.

 

[JayBee425]

Seat frames are the same. I am the UAW chairperson at the seat plant

 

[mja]

Seat frames are the same. I am the UAW chairperson at the seat plant

Thanks JayBee! Good to know we have some first hand expertise on the forum.

 

[mja]

Does anyone have a wiring schematic for the heated seat circuit?

edit: found it...
http://www.sonicownersforum.com/forum/chevy-sonic-owners-forum/8352-heated-seats.html

 

[carbon02]

Stimpy2301-

Thanks for the great post. I have a 2012 Cruze, and while I'm not 100% certain the seats are identical, I bet the method of construction is similar enough.

I don't have heated seats, I actually have cloth. Been thinking of installing the Dorman universal heating element under the factory cloth.

I think I can access the bottom of the seat the same way you did, but I wouldn't have to fully remove the cushion right? Just slip the heating element between the cloth and the foam? Now doing the seat back I could do the same thing?

Without dealing with the Hog Rings?

Also for those that have problems with the factory elements keep an eye out for dorman to consider making the heating element if there's enough demand.

Thanks- Carbon02

 

[stimpy2301]

I don't have heated seats, I actually have cloth. Been thinking of installing the Dorman universal heating element under the factory cloth.

I think I can access the bottom of the seat the same way you did, but I wouldn't have to fully remove the cushion right? Just slip the heating element between the cloth and the foam? Now doing the seat back I could do the same thing?

Without dealing with the Hog Rings?

No, you won't be able to get the heating element in there without dealing with hog rings.

Reference the locations:

No matter which direction you come from, there will be hog rings pulling the upholstery down to the foam, blocking heating element insertion.

Interestingly, a quick image search (to look at the Dorman kit) makes it look like it comes with hog rings & hog ring pliers.

 

[carbon02]

No, you won't be able to get the heating element in there without dealing with hog rings.
.

Thanks for the great picture. I've done a little googling for hog rings to understand how they are used in upolstery.

The Hog Rings are what gives the seat cover it's defined shape, the "lines and contours" so to speak. The hog ring holds the cover down to the foam. I also read that some seat's use velcro, but honestly I can't see that working really well.

There have been posts over on Cruzetalk of trying to use factory components to do this, but unless someone had line of sight to really cheap complete seats out of a recycler's yard I can't see doing it that way. I know the Cruze without heated seats is missing part of the wiring harness, and potentially a control module under the seat itelf to control the heating.

I now understand why Pep Boy's has a universal kit like this that's been opened and returned in their store. Removing the cover seems easy, and probably is, after you've done it a few times!

I just checked Dorman. There is no OEM kit for Sonics or Cruze yet, but I know they did OEM fit kits for the Bonnevilles because a family member had heated leather go out, and that was a potential solution.

I assume most Hog Rings used for Auto Upolstery are 1/2"? I may look at alternatives to the Dorman, as even that offering is $150 to $200.00. I need to search around for prices.

Thanks!

 

[mja]

There have been posts over on Cruzetalk of trying to use factory components to do this, but unless someone had line of sight to really cheap complete seats out of a recycler's yard I can't see doing it that way. I know the Cruze without heated seats is missing part of the wiring harness, and potentially a control module under the seat itelf to control the heating.

Going to attempt this at some point. For now just purchasing the foam so I don't have to reinstall the heated seat foam in the future when I get to the wiring. It looks like all that is needed after the seat foam is: the heater control unit which is attached to a bracket under the driver seat, stock heated seat console on the dash, fuses, and connectors (or make your own connectors). Follow the stock wiring diagram and then have a dealer update the ECM with the correct RPO/VIN... hoping it all will work. If not I'll just rig it up to work with the stock console buttons w/out the ecm controlling it. But if anyone has done this or has any advice, please let me know.

 

[stimpy2301]

The Hog Rings are what gives the seat cover it's defined shape, the "lines and contours" so to speak. The hog ring holds the cover down to the foam. I also read that some seat's use velcro, but honestly I can't see that working really well.

Actually, the velcro does work very well too -- and is certainly a hell of a lot easier to undo/redo ... though it does come with the scary sound like you're tearing the seat fabric, lol.

My Tiburon's backrest had a combination of velcro and hog rings, as I discovered when installing heated seats there. See below:

CLARIFICATION: The photo above is a 2004 Tiburon, not a Sonic.