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New "How to fix the seat heater" thread.

109K views 74 replies 50 participants last post by  ChevyGal2005 
#1 ·
Hey everyone....I needed to re-do this thread because my picture host went belly-up. Anyway, here goes:

Hey everyone! I had seen multiple posts about this problem while I was searching for a "How to" on changing out the p.o.s. seat heater coil that GM graced us with. Well it seems that nobody had replaced one themselves, or at least nobody was giving any hints on how to do it, so I decided to try my hand at writing my very first "How to" thread. So....here goes:

I ordered the Dorman replacement unit from RockAuto.com (Part number 641107). The unit was $67.00 + delivery charges. It took about 4 days to get it. (You can also order the OEM unit from GMPartsDirect.com, part # 88949407, for about $80.) Here is what comes in the Dorman package:


It also includes this pair of pliers and a bunch of clips:


Now to get to it:

1st adjust the seat so that it centers the bottom cushion over the seat rails. Lean the back of the seat slightly backwards for easier removal of the bottom cushion.

Next you need to unplug your battery so you don't fry anything important. You will need an 8mm wrench or socket to pull the negative battery cable off.

Now it's time to remove the whole seat. Start by removing these caps:


2 of mine had broken clips that hold them on. (We bought this TB used. It was 2 years old.) The unbroken one required a small screwdriver to pry the clip open so the cap could be removed. Be careful not to break the clips. There are 3 caps in total.

Under each cap there is a nut:


Remove these 3 nuts with an 18mm socket. They do require a decent tug to get them broke loose. The fourth "corner" of the seat is held down with a bolt, not a nut. It is the same size as the 3 nuts.

After removal of the nuts and bolt you will need to lift the seat off of the studs the nuts were on. I lifted and slid the seat rearward about 3 inches. Then I tilted the whole seat backwards so I could disconnect the wires underneath. There was only one connection. It is purple and black and it
looks like this:


To disconnect this plug you need to squeeze the black tabs together at the bottom and pull on the purple lever. Once this is done the plug easily comes apart. (There is a diagram on the back of the plug showing how to do it if you need help.) Mine also has a little yellow plug, as seen in the picture, that has a jumper in it. I don't know what it is for, but it was never plugged into anything.

Now, you will need to lift the whole seat out of the vehicle. (I would say the seat assembly weighs about 80 lbs. Get help to lift it out if needed. Don't hurt your back.) I placed an old, clean bed sheet on the floor in the garage next to the TB and placed the seat on that to keep it clean. Set it down so that you have access to the underneath side of the seat.


With the seat out of the TB I decided to remove the bottom cushion from the rest of the seat. To do this you will need a 13mm deep socket or 13mm wrench to remove 4 nuts, 1 from each corner. They look like this:


Once all 4 of these nuts are removed, you can lift the bottom cushion off of the seat frame. There are a couple of plugs that need to come apart to remove the bottom cushion. The hardest one is plugged into the black box under the seat cushion. I had to stick a small screwdriver down the hole and pry on the locking mechanism to pull it out. Other than that it was a piece of cake.

Now, a word of caution: There are some sharp parts on the seat frame that can cut you open pretty good if you are not careful. I was not careful.


After a little bit of TLC from my wife, and a band-aid, I was ready to get back to work.


This picture is of the connector that goes to the heating element. Disconnect it.



Now we need to remove the leather cover and foam pad from the springs/frame. Start by removing these two clips. (I used a small screwdriver to stick inside the clip and pry it off of the metal frame.)




Now go to the back of the seat cushion and remove the clip that holds the leather to the frame. It looks like this:



Here is a picture of it un-clipped:



This picture shows the velcro that holds the heating element cord out of the way. Pull it open and pull the cord out of the flap.



Next, you need to remove the panel that holds the seat controls. It requires a long phillips screwdriver to get to the 3 screws.



With the controls removed it is time to pull off the clip that is holding the front of the leather to the seat frame. It is very similar to the back clip and it comes off pretty easily. With all of the clips removed the foam cushion and the leather cover will come off of the steel frame. I took the cushion into the house to remove and replace the heating element. When I started to pull the leather off of the foam I found out why my heating element quit working. It had burned one of the wires completely in half, and burned the foam cushion and the underside of the leather seat cover. Check out the picture:



Now comes the hardest part of this whole deal. There are a bunch of steel clips that hold the leather to the foam cushion. There are three at the seam toward the front of the seat that goes from left to right that must be cut and removed in order to swap the heating element. They look like this:



The 3 clips need to be cut with ***** and completely removed from the cushion and the leather tab. I used needle nose pliers to fish the clip out after I cut it. Tip: Don't just yank the clip out of the foam. It goes around a wooden dowel that is embedded in the foam. Do not break the dowel or pull it out of the foam. You will need to replace these clips with the ones that came with the heating element. Leave the other clips in the seat. You do not need to remove them, unless you want to. They are a huge pain to replace, at least they were for me.

The next step is to remove the heating element. It is stuck to the foam cushion with double sided tape on the sides and across the front. You need to pull up on the corner of the heating element and carefully remove the element from the foam. Be careful not to pull big chunks of foam off. Shimmy your hands down under the sides until it is completely un-stuck from the foam, then simply pull the element out. Mine looked like this when I got it out:



And this is what the inside of the leather cover looked like:



Now compare the original heating element to the new one. In this case they look exactly the same.


To install the heating element I slid it underneath the leather cover and matched up the edges with where the original one was. (You will be able to see where the old tape was stuck.) I started with the front edge and peeled the backing paper off of the tape and stuck it down. (Make sure the cord is coming out of the same side of the seat as the original one was!!) After sticking the front down you need to replace the metal clips that were cut. This was the hardest part for me. I stuck the clip into the foam and around the wooden dowel. Then I stuck one side through the leather tab and then I tried to squeeze the ends together with the pliers they supplied. Apparently I am not an upholstery genius because I couldn't get the pliers to crimp the clips at all. I resorted to using the needle nose pliers for this, too. It didn't turn out as nice as the stock clips, but it worked. Try to point the ends of the clips downwards so you don't get poked when you sit on the seat.

After the clips were replaced I stuck my hand under the element and peeled the backing paper off of the tape that runs down both sides of the heating element. (One side at a time.) Stick them down and then pull the leather over the foam cushion so it looks like this:
 
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#33 ·
HUGE thanks to gofast for this, I bought my 03 this spring and this was one of the few problems with it that warranted the killer deal I got. I wish I would have thought about fixing it this summer, but of course you don't think about silly things like warmth until it's annoyingly cold to do repair work...

Also thanks to whoever provided the tip on checking to make sure the heating pad is the problem. Picked up a DVM today and will check it tomorrow. I tried checking it now but I couldn't get the green clip loose without unbolting the seat and I don't have a socket set on me. Just a little too tight under there. Anyways, thanks again for the how to thread, both my driver and passenger seat bottoms need fixing (backs are fine as seems common) and now I know how to do it!
 
#34 ·
Checked with voltmeter and I got power going to it, which I suppose I should know since the back heaters still work. Only thing that bothers me is that I can pick up an after market seat warmer that straps on to the seat for like 20 bucks at Canadian Tire. I gotta do both seats here and $40 sure beats $200. But I guess what's the point in having the feature built in if I'm not gonna use it? gah!
 
#35 ·
Thanks op, very helpful tread, great pics too.

I did mine yesterday (04 Rainier) decided to leave the seat in & just remove the bottom cushion. I raised the seat up all the way, & the 4 nuts were easy to get to. The biggest problem is trying to figure out how to release all the electrical connectors underneath. There were about 5 of them & they all seemed to have a different method to unlock. Pretty sure if you remove the whole seat, you only have to release the big one, which if the easiest to figure out. Then you can do the others with a much better view with the seat on its side.

The rest of the job was much less frustrating, thanks to all the good info from this thread. Start to finish, even with struggling with the connectors, was a little over an hour.
 
#39 ·
This was a great write-up!

It figures, I removed the seat, did everything according to instructions, everything went perfect, but I never read (or printed) the last page of this write-up.

Our 03 Envoy had the BACK heating element go out, not the seat part. After following all the instructions here, and seeing all the pictures, I assumed the heating element was for the base cushion AND the back. That's what it looked like in the picture of the element, where there's a large and small portion. I assumed the material between those portions was for where the seat transitions to the back.

Now I have the entire assembly out, only to read that this procedure (and the Dorman unit) was only for the bottom cushion, not the back!

Now what? :hopeless
 
#41 ·
Thanks!

Is there a procedure for replacing the back heater?

I was surprised that when I finally removed the bottom portion of the seat (following all the steps in this thread), and there was no connection to the seat back. How is the seat back heater connected to the seat cushion heater?

I just did a search for the Dorman 641-106 on Amazon, and they say it does not fit my 2003 Envoy SLT. :(
 
#42 ·
for starters , amazon sucks as a reference for car parts

if you are adept enough to tear into a seat repair--- surely you can see the electrical connection for the BACK heater pad- LOOK FOR IT

Then go to dormanproducts.com and look at the pic for that part number.

( yes, i know it doesnt list it for your 03 envoy-- but i'll just bet its the one you need)

OR

if you prefer the DEALER ROUTE, here is your officail GM part number

Heater pad-seat back part #
GMC 88949455
 
#43 ·
Thanks ce8204.

I realized after submitting that post that there must of course have been a connector for the back of the seat controls, I just didn't notice any plug coming out of the bottom of the back part of the seat.

Is there a procedure for removing the back heater pad?

What's weird is that the Dorman part # for the cushion part (described in this thread) has instructions showing that the heating element is for the cushion AND the back. That's one reason I don't trust these Chinese/Taiwanese instructions. Delco isn't any better, all their parts are sourced from overseas now, so they don't have any better quality than the cheap Taiwanese junk.
 
#47 ·
Just replaced my Seat Heater Elements

Thank you Goatfaster for the excellent how-to write-up ! The pictures aided immensely. :thumbsup:

My wife and I did both seats together in about 3 hours. This was a very relaxed pace and included wine (after we completed one seat....celebration time).

If anyone is worried about performing this work, don't be. The connectors can only go together one way as they are all unique. And definitely the metal hold-down clips were the hardest to install. Hard may not be the best descriptor. Dexterous Manipulation resulting in hand-cramps is a better term (lol). We used 2 needlenosed pliers instead of the supplied tool you get with the Dorman replacement parts. (Note: I bought the parts thru Rock Auto).

Now we can have warm bums in the -30 deg winter....which is approaching.
 
#49 · (Edited)
Nice write up! Did this in about 2 hours today, pretty easy.. Here are my thoughts/ hints.

Seat Position. Obviously as poster said, make the seat line up on top of the tracks, but the position of the seat up and down, I took mine with the seat all the way up... Problem with that is that made the 13MM front driver side bolt on the seat bottom harder to get out because the position joint is right below it. I had to wrench the bolt a bunch of times because the socket head was too big to fit in there even with a shallow socket... If you put the seat all the way up, then down for a few seconds, maybe 3, then the joint is enough out of the way as it turns horizontal.... Rest of the 3 13 MM bolts are easy access, just the front driver on had the joint just below it...could have saved me a little time, not a big deal...

I found it easier just to remove the whole seat, with the 4 18MM nuts/bolt. Easier to work on in the living room with plenty of light to see underneath all the motors and wires..Personal preference for lighting.

Sounds silly but for us that have never done this, make sure the new seat heater you bend the end with the smaller pad into the cushion grooves. When I took off the sticky tape and put it on, it obviously was longer than the original pad heater footprint, I didn't push the heater into the pad groove..Doh...When you do that and make it exactly as the old, it fits perfectly..

Hogs Rings. With the foam pad in the way, I couldn't get the cheapo rad handled hogs ring pliers to work.. When I pushed them in, it would grab the seat upholstery plastic tubing, but not get around the wooden dowel in the seat cushion... I just used needle nose pliers, pre-bent the new hogs rings into a U. Then at the end of each hogs ring I put a little bend in to form a circle, keeping the circle open enough to get around both the plastic tubing and wood dowel...

From factory the back of the new Hogs Rings are flat...Instead bend it into a U, and bend the ends into a circle angle then stick each one in the wooden dowel in the cushion with the point ends sticking up... Then take the upholstery and put one end of the hog ring through it using the existing hold in the fabric, that way you know you're lined up. Then as you fight the cushion from pushing out the fabric off the new Hog Ring, take your other hand and take needle nose or linesman's pliers and Squeeze the Hogs Rings shut around both dowels. The existing U you bent earlier into the Hog Ring will form around the Wooden dowels easily, not breaking/damaging them....Then turn them down to avoid pointy ends pricking through fabric, but since we had the pre-made circle ends when you clamp/crimp them down, the circle ends automatically go around the wood/plastic dowels...I turned them down anyway, probably didn't have too..use common sense feel, if point bend around.

Pretty easy fix once you get the hand of it. I found with the new Hog Ring in the cheapo red handled pliers, that not enough of the pointy end of the hog ring was sticking out to get past the wooded dowel...What a cheapo tool...
 
#50 ·
About those hog rings.........28 years ago I was re-upholstering the seats for my '67 GTO. First time I've ever done it. Also was the first time I've ever gotten 2 black eyes at the same time.

I was struggling with the cover, trying to pull it into position almost as hard as I could. Suddenly it slipped, and the hog ring equipped pliers came straight at me at the indent on my nose. I almost passed out, started bleeding pretty badly, almost stuck the hog ring thru my nose bone just below the eyebrow line. I guess I was trying to pierce my nose, found out it's not for me :duh:

I've since learned to get those new covers warm. Old covers like in a TB that you are only replacing heaters, they go back on no problem.
 
#51 ·
A Little Simpler Way

Great write-up! I found it is not necessary to remove the entire seat from the vehicle. The four nuts holding the seat bottom to the frame are accessible with the appropriate assortment of long and short 13mm sockets/wrenches.
First, remove the control and side panel from the seat. Leave the controls plugged in so you can move/tilt seat as needed to gain access to the nuts. Once you have removed the four nuts, lift the seat up off the frame. Then disconnect whatever plugs you need to and follow the write-up from that point.
 
#54 ·
Thank you for taking the time to write this post. It helped immensely. :)

It seems that the point of failure is the valley between the forward and rear sections of the "butt" part of the heater (obviously). I removed the adhesive covering of the rear section and stuck that to the foam. Then I pushed the front section back creating some slack to follow the contour of the valley. Removed the sticky backing and stuck the front part to the foam.

Pic:


Only problem is I find myself pressing the "back only" button cause the seats too hot. :duh:
 
#55 ·
Just want to say, you did an outstanding job of making a scary repair:tiphat:tiphat:tiphat:tiphat look simple. went a winter without my seat heat. Hated that. Now going to try it. Can you imagine this at at shop. labor alone would have been 350 to 450. Most of them double the price of parts so thats at least another 160. Even if it takes a whole day, I don't' make 500 a day. So this job pays me and pays me well. Thanks.
 
#56 ·
Great thread.

I replaced mine in about 90 minutes taking my time.

I cut out 6 hog rings (just using standard wire cutters) to make the heating element re-install manageable, but since I had a set of hog ring pliers and 100x rings, it wasn't a problem.

On a scale of 1-10 of difficulty, this job was about a 3 or 4. Low to medium difficulty if you have the correct tools.
 
#57 · (Edited)
Do I have a different problem?

My back part works fine by itself, the lights come on and everything. The seat cushion however doesn't do anything. No lights, no click from the box, nothing.
I swapped the ECM from the passenger side and had the same results. The drivers side ECM worked perfectly on the passenger side.
Does this mean that the drivers element needs replaced? I didn't see any confirmation of the lights in any of the posts.
Thanks for any advice.
 
#58 · (Edited)
My back part works fine by itself, the lights come on and everything. The seat cushion however doesn't do anything...
...Does this mean that the drivers element needs TO BE replaced?
FIFY.

The bottom-cushion element is almost certainly burnt-out.

Test the seat bottom element with an ohmmeter. If there's an open circuit, the element has burned through.

I'm tempted to say you should just remove the seat and bottom upholstery, as the heating element is just about guaranteed to be popped--but I suppose proper testing is always a good idea.
 
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