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  #1  
Old 01-28-2009, 07:23 PM
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GOFASTER GOFASTER is offline
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New "How to fix the seat heater" thread.

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 dykes 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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  #2  
Old 01-28-2009, 07:23 PM
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Now you should be ready for re-assembly of the bottom seat cushion to the steel frame. Start by turning the cushion upside down and placing the steel frame on it. I matched up the springs to the depressions they left in the foam
to line everything up right. Then I started with the front clip and attached the leather cover to the steel frame. Then I did the side clips, then the back clip. When you are finished it should look like this:



Next, make sure you route the cord from the heating element through the same flap that is held shut with the velcro. Remember to plug the heating element cord into the connector, too!! Put the three screws back into the control panel and attach it to the side of the seat.

Now you are ready to re-assemble the bottom seat to the rest of the frame. Place the bottom assembly close to the seat frame and plug in all of the connectors that you disconnected before. Make sure you get them all--I almost forgot the seatbelt connector. After all the connectors are in place slide the four studs on the bottom of the seat cushion assembly through the four holes in the seat frame and tighten the nuts that you removed previously with the 13mm socket. (I don't know the torque #'s. I just made them tight.)

Now all that's left to do is to pick the seat up and place it in the vehicle. Remember, it is kind of heavy and you may need some help. I placed it 3 inches behind the studs, leaned it back and plugged the connector in. (Remember to lock it into place with the purple lever.) Now, lift the seat over the studs and replace the 3 nuts and the one bolt with the 18mm socket. (Again, I do not know the torque #'s for these fasteners. I just tightened them up pretty good.) Don't forget to put the caps back over the nuts. Hook the battery up with the 8mm wrench and go for a test drive. Now you have a seat heater that works!!

This whole process took about 4 hours, including first-aid and lunch. (I believe that this write up took longer than the swap.) I'll try to answer any questions that you might have........
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  #3  
Old 01-28-2009, 07:38 PM
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Great writeup. This is what I've been looking for.One question. How did you determine that it was actually the heating element? I have the same problem where only the bottom heater does not work. The "back only" button does not light up, regardless if pressed not. Is this the same case as yours?
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  #4  
Old 01-28-2009, 07:52 PM
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Quote:
Originally Posted by LIL_MAC View Post
Great writeup. This is what I've been looking for.One question. How did you determine that it was actually the heating element? I have the same problem where only the bottom heater does not work. The "back only" button does not light up, regardless if pressed not. Is this the same case as yours?
I am not sure if the "Back Only" light would come on or not? This is my wife's vehicle and I only drive it occasionally. One time when I did drive it my leg was burning in one spot then shortly thereafter she told me the lower part of the seat heater was not working. I looked on this forum and found that several others had the same experience, a really hot spot on their leg. One of those people said that they had taken theirs in to get replaced twice, but nobody else had fixed theirs. So, I decided to try it out and this thread is the result of my attempt. Good luck! (If you want to tear your seat apart before ordering the replacement element "just in case", it only takes a couple of hours to do so. Then you can just pull back the leather seat cover and check to see if it's burned. Heck...You could probably check it by just pulling the seat out and prying the clips off that hold the leather seat cover on. Less than an hour to do that.)
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Old 01-28-2009, 07:56 PM
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Thanks for the tip. That's what I might end up doing before buying a brand new heating element. You don't happen to know what caused the burned out wire do you? Is the new heating element superior in design to the old one in any way? I know you mentioned some folks having to have it replaced several times. It would be a bummer to go through all that and have it fail next winter.
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Old 01-28-2009, 08:23 PM
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Quote:
Originally Posted by LIL_MAC View Post
Thanks for the tip. That's what I might end up doing before buying a brand new heating element. You don't happen to know what caused the burned out wire do you? Is the new heating element superior in design to the old one in any way? I know you mentioned some folks having to have it replaced several times. It would be a bummer to go through all that and have it fail next winter.
Actually, the new element looks almost exactly like the original. As for the cause, the unit dips down to go through a little valley where those steel clips attach the leather cover to the foam and I think the resulting "u" shape gets hot and burns through. I told my wife to run it on the middle heat setting to see if we can make it last longer.
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  #7  
Old 02-24-2009, 02:05 PM
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rreimund rreimund is offline
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Thanks for this write up.. just what I was looking for.. Glad (maybe not glad, but at least less upset) to see that I'm not the only one experiencing this exact issue.

That said, I'm concerned about that failure.. I mean what kept if from just lighting the whole car on fire? I guess it's not such a big deal because it won't run unless you're in the car. With my remote start, if the on/off state were to be kept between starts I'd be more concerned (i.e if it was on when I turned off the car and remained on when I remote start it).. but thankfully it doesn't do that.

Oh, and those clips I believe are what they call "Hog Rings" and they are the toughest part of upholstery. Thanks again. I think I'll be doing this in the next month or so, as soon as we get a nice weekend.
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  #8  
Old 02-24-2009, 08:35 PM
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Quote:
Originally Posted by rreimund View Post
Thanks for this write up.. just what I was looking for.. Glad (maybe not glad, but at least less upset) to see that I'm not the only one experiencing this exact issue.

That said, I'm concerned about that failure.. I mean what kept if from just lighting the whole car on fire? I guess it's not such a big deal because it won't run unless you're in the car. With my remote start, if the on/off state were to be kept between starts I'd be more concerned (i.e if it was on when I turned off the car and remained on when I remote start it).. but thankfully it doesn't do that.

Oh, and those clips I believe are what they call "Hog Rings" and they are the toughest part of upholstery. Thanks again. I think I'll be doing this in the next month or so, as soon as we get a nice weekend.
Hog rings, eh? I guess that's what they look like. Good luck with your swap.....It was a lot easier to do than I thought it was going to be!
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Old 07-08-2009, 08:27 AM
goblue goblue is offline
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Wow..thanks for the incredible post. Got mine done in about an hour, and that included talking to the paperboy.

Couple of things I should mention:

o I found to help diagnose the problem, you can unhook the wire to the seat heater and test it with a voltmeter. If you get voltage out, you know it's probably the heater pad. I went to the trouble of removing the seat and getting an ohmmeter on the heater pad. It was open, so I knew that's what the trouble was.

o I couldn't get the connector off of the control module on the bottom of the seat. Ended up pulling the other connectors off, unscrewing the module and "leaving it behind"

o When I removed the seat cushion, It spun around and snapped off the wire for the seat belt sensor. No biggy really..I didn't bother to hook it back up and with the wires severed, it just thinks the seat belt is always plugged in.

o I found I only had to remove 2 of the hog rings...was able to slip the heater in without taking the third one out. I reused the same hog rings.
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Old 07-08-2009, 08:30 AM
goblue goblue is offline
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Failure mode

Oh..as for the failure of the seat heater. In my opinion what happens is the wire makes a bend when it goes through the "hog ring" section. The constant getting in/getting out of the seat flexes that wire. Over time, strands of copper break, and at some point, too much current is going through too few wires and they burn out.

I don't think it has anything to do with what heat level you run it on..but more, how much flexing the seat takes.
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