99 Suburban heated seat

Can anyone tell me why the driver's side heated seat does not work, but the passenger's side does on my 99 Suburban, K2500, LT?

Howdy: It could be any of these things: 1.) The switch. 2.) the Left Front control module. 3.) The seat elements. 4.) wiring problems. A module check can be done by swaping the left and right ones. They are located under the seats.........Steve

What does the module look like?

What does the module look like?
Small. About 2" square. Located at front of seat below cushion. Looks like a bear to get to. Good luck.........Steve

I am sorry man, I am not finding it. Do I have to take part of the seat apart to get to it or should I be able to see it? Thanks again, Dan

Dan: I couldn't see mine either, but I could feel it. The book says to remove the mounting bolts and tip the seat back for access. Mine was in the center above a cover of some kind. Follow the wires, six of them. Orange=12v hot at all times from the "front heated seats" fuse under the hood. The rest are yellow, black, Lt blue, Lt blue/black and pink/black.
Steve

Steve,

I FOUND IT!!! Now that I found it, do I really want to dig into it??? Ha. I am trying to sell it and wanted to fix this first... hmmm It looks like someone else has already gotten into it at one time. If I am going to take practically pull the seat out I think I am going to find out how much the element cost and maybe just go ahead and replace it, if it is not too expensive. I am definetely not going to remove the left one to try it in the right one.

Thanks,
Dan

Steve,
I forgot to ask, what book are you using for the information?
Thanks again,
Dan

Dan,I don't know if you recieved my e-mail about heated seats,but to replace the element,GM sells the entire cushion to replace the lower heating element.It's very expensive.It may be posibble to get just the element from your local parts store,but either way the job will involve tearing down the seat to replace the cushion assembly or just the element.A quick check to see if the module works is to turn the ignition on,seat belt buckled and then turn the switch on.If you don't hear a slight click sound(module relay energized),you have to make sure power is getting through the seat switch and the seat belt buckle switch.By using the passenger seat module you will be able to find out if the seatbelt switch and seat switch are functioning properly.If this works,the modules are not all that cheap either.I was quoted 100 dollars from GM.I was able to locate GM modules(25638146) at a discount store for less than 20 dollars.If the module does energize,the problem will be the lower seat heating element or the thermostatic switch within the heating element.With a break in either component,the circuit has an open and the seats will not heat up.I hope this helps to get your seat fixed.
chuck's

Dan: 1998 Second Edition C/K Truck Service Manual. My Sub is a '99 by VIN although it was made in early '98. That's why I got the '98 Manual and so far it's been pretty good.

I have a '99, one of the earliest, I took receipt of it in June of 1998. I had the same problem in 1999. The dealer replaced the whole seat lining/cover to fix the heater. Both seats were fine until around 2002 - then the passenger seat started working for everyone except my girlfriend. The only thing I can figure is she is too light, to make the broken connection in the seat arc (or work). Recently I have noticed that the replaced drivers seat cover is now intermittant (and I hear a buzzing noise sometimes - and immediatly shut it off).



Can anyone tell me why the driver's side heated seat does not work, but the passenger's side does on my 99 Suburban, K2500, LT?

bn2wild.The buzzing sound you are hearing could be the relay within the heated seat module.If you are eneregetic and adventurous,you could try the module from the passenger seat and put it in the drivers seat.If you have read the previous posts,you know it won't be easy.If the module has GM #25638146, it could be possible to get the module for about $20.I hope this helps
chuck's

I have a problem were all of a sudden both heated seats stopped working.....would that by a fuse maybe? what could that be?:banghead:

I have a problem were all of a sudden both heated seats stopped working.....would that by a fuse maybe? what could that be?:banghead:

2 fuses. Underhood fuse block 20a "FRONT HEATED SEATS". Instrument panel fuse block 10a "RR HVAC".

I have a similar situation on a 98. I was able to reach under the seat to pull out those modulators (25638146) and swap the working side for the non- working side. Both mods work in the good side and not in the broken side.

While the switch itself and the pins the modulator connects to operate the same(using a test lamp), the modulater does not 'click' on the 'broken' drivers side.
Is this a result of a bad element? It's odd that the wiring functions the same on both sides.

Thanks for any help.
Chris

In a previous post I mentioned about the heated seat switch and the seat belt buckle switch.From my experience,if either one does not work,then the "click" sound within the module will not work.My lower seat cushion elements do not work,but my module does "click".Other than that, if you can check for power to the lower element from the module,that would be my next check.I hope this helps you along.
chuck's

Thanks, Chuck's.
I guess I'm having trouble being certain the seat belt switch and/or control switch functions properly. I cant seem to identify what the working side does differently than the other!
I lamp tested the working side, at the modual, and got orange -hot always, and the pink stripe -hot only when the unit is set to med or high. The non working side functions the same.
My belt warning does work normally. My Chiltons and Haynes both fail to show a diagram on the seats.

Do any of theses wires go to ground to function? I have tried to get lamps to light on the other working side wires without success.
Thanks again.

Check for a voltage at pin B of the module with the switch on,seatbelt buckled and ignition on.There should be two voltages,one greater than the other.(hi or low position)If no signal there.I believe the relay in the module will not energize.As you stated,the pink with black stripe wire should have power when the swicth is turned on.Power to the elements come from pin A on the module.I hope this will help.
chuck's

Thanks again for the help.
I do get voltage at B, but do not at A. Incidently, I get volts at B even w/o the belt buckled, if that means anything.

What is the source of "A" 's voltage? The switch seems to function as indicated by the b volts, and I do not get voltage on 'A' on either side.even on the side that does funtion normally.

Thanks

If the module is working on the good side,there has to be a voltage at pin A because the elements get their power from this pin.It could be possible that the seat temperature sensor is inoperable.I think that if the module does not get a signal at pin E the module may not energize.As the seats heat up.the sensor controls when the the module comes on or off.Using an ohm meter check for continuity of the sensor.Four pin connector with the black/red wire at pins C and D.I have run out of suggestions to help you.I hope this will fix your problem once and for all.
chuck's

Much Appreciated. I may have to use a more sensitive meter and be more diligent to detect the pulses. I'm going to continue to compare sides till I get a discrepancy, may be put jumpers wire between the mod and its connector on the good side and remove them one at a time till I match the non working side, then trace the source. Thanks for the help. it may be a couple weeks before I get back to it.

Chris

Hello,
i have a 99 K1500 5.7 and my passenger side heated seat went out along with the little light on the window button on the passenger side door about the same time,could this possible be wiring related issues.
Thanks

Is anyone still following this and/or has there been anything figured out?

I have a 99 Suburban as well and the driver side heated seat doesn't work. I found that the top cover/element ohms out as completing the circuit, but I can't get the bottom cover/element to ohm out. I compared it to the passanger side and have different readings.

I have an aftermarket element that I was going to install but upon tearing the cover off, I decided it wouldn't work because GM used velcro to hold the tucked areas down and the aftermarket called for holes to be cut a max of 1" and to use hog ring staples.

Has anyone used an aftermarket pad on these or know of a good way to "fix" the element? it seems to be "built-into" the cushion.

BTW...from what I could gather the top element will only work if the bottom element works. It appears that the module is energizing as I hear noise from it when I turn the seat on. With this and considering the bottom element doesn't ohm out, I'm assuming that is where my issue lies.

One more thing for others, checking the resistence of the element is easy to do and you don't even need to pull the seat, you just have to access the harness for the top or bottom seat cushion. The plug for the top pad is just under the area where the cover "zips" together and contains a black and purple wire. The plug for the bottom pad is in the center rear underside of the seat, it is a 4 prong plug with 2 yellows and two blacks. Judgeing from my passenger seat the yellows should ohm across, I got a reading of 15 or so on the black wires. Not sure what that was....

Yes, it would be nice to have the heated seats to work.I investigated my seat problem only to find that I had a module and seat element nonfuntional.Without looking into aftermarket elements,I just put a jumper wire into the four prong connector to get the upper element to work.The draw back from doing this is that the temperature control switch is also bypassed.Good luck with your challenge.

chuck's

Yes, it would be nice to have the heated seats to work.I investigated my seat problem only to find that I had a module and seat element nonfuntional.Without looking into aftermarket elements,I just put a jumper wire into the four prong connector to get the upper element to work.The draw back from doing this is that the temperature control switch is also bypassed.Good luck with your challenge.

chuck's

Did you jump all 4 wires on the 4 pin harness or just the two that go to the element? Like I believe I mentioned, I have 2 yellow and 2 black wires. I think the yellow went to the element and the black were probably the temp sensor.

Thanks for the reply,
Brian

I can't remember it all,but if you have a wiring schematic it will help with my explanation.Basicly the power goes to the lower element,then up to the upper element.I would take the lead that feeds the lower element and back probe the pin to allow me to put the power to the upper element.The four pin connector is marked A B C D.I believe I placed the jumper from pin A to pin B.This bypasses the lower element and puts power to the upper element.Remember that there will be no seat temperature switch.I hope this explains better.

Chuck's

I don't have a diagram, but I can probably figure out which lead feeds the upper. I believe it is the wires that are yellow on my 4pin plug, the same wires that seem to have a short/open. I will see if I can find the letters A B C & D.

You don't have to respond if my next question is correct, but without the seat temp switch, the seat will just continue to heat up until you turn it off correct? Meaning, I would have manually turn it off, when/if it gets to hot. I would also assume, that could pose a fire hazard, if left on too long, but being as it is the driver seat and obviously someone would always be in this seat when the vehicle is running, that danger should be very low.

Thanks again for your help....

Yes ,you are correct about the temperature switch.The letters A B C D will be on the outer shell of the connector.They will most likely be small and hard to see.
chuck's

Well, I've been dealing with no heated drivers seat for a couple of years now, and I finally decided to tackle the issue this week. I was able to come across a wiring diagram (PM if you'd like it) and I did some testing with the seat out of the truck.

What I found was an open circuit in the lower (butt) heating element. Like it was stated earlier, the circuit for the element is the two yellow wires in the 4 wire plug (I'd have to double check to see the right letters on them).

I decided to pull apart the seat, because that's what engineers do. This was much easier of a process than I thought, just clip the hog-rings and the seat cover comes off without any effort.

What I found was a nice burn in the foam of the seat cover, which is exactly where the broken wire was found. After taking a quick look at it, it was just a simple wire jumper that was pinched apart by the seam of the seat. This jumper connected the two small blue heating element wires that keep my butt warm. I simply peeled back the foam, cleaned up the part that pinched the wire apart, and soldered a nice new jumper wire into the mix. After some research online, I used a 14AWG, primary wire from the auto store, most of us have a piece or two lying around (3" is all it took). I couldn't find hog-rings or pliers for the life of me, so I just used some sturdy tie-wraps to put the seat back together, time will tell on that issue.

Took a test drive and my rear end was very happy, as well as my wallet. This repair cost $0, and fixed a problem that was around for way too long. It really didn't take any special tools, and it also didn't require a whole lot of muscle.

Let me know if you have any questions about the repair, I'd be happy to give some advice.

Well, I've been dealing with no heated drivers seat for a couple of years now, and I finally decided to tackle the issue this week. I was able to come across a wiring diagram (PM if you'd like it) and I did some testing with the seat out of the truck.

What I found was an open circuit in the lower (butt) heating element. Like it was stated earlier, the circuit for the element is the two yellow wires in the 4 wire plug (I'd have to double check to see the right letters on them).

I decided to pull apart the seat, because that's what engineers do. This was much easier of a process than I thought, just clip the hog-rings and the seat cover comes off without any effort.

What I found was a nice burn in the foam of the seat cover, which is exactly where the broken wire was found. After taking a quick look at it, it was just a simple wire jumper that was pinched apart by the seam of the seat. This jumper connected the two small blue heating element wires that keep my butt warm. I simply peeled back the foam, cleaned up the part that pinched the wire apart, and soldered a nice new jumper wire into the mix. After some research online, I used a 14AWG, primary wire from the auto store, most of us have a piece or two lying around (3" is all it took). I couldn't find hog-rings or pliers for the life of me, so I just used some sturdy tie-wraps to put the seat back together, time will tell on that issue.

Took a test drive and my rear end was very happy, as well as my wallet. This repair cost $0, and fixed a problem that was around for way too long. It really didn't take any special tools, and it also didn't require a whole lot of muscle.

Let me know if you have any questions about the repair, I'd be happy to give some advice.

I would love to have a copy of that diagram if you can send it to me at [email protected]. I do appreciate it.

As far as the short, maybe I'll tear my seat back apart and see if I can find something like that. Can you tell me where exactly on your seat this happend? I don't recall any burnt looking spots, but I would bet it would be close to where your problem is, considering this seems to be a popular issue.

Also, what did you use to cover the solder connection? Can you put some heat shrink over that or is something else better?

Thanks again.

As for the wiring for the upper element, what I found was that the 4 pin plug (ABCD) is just for the lower element and the thermistor. The upper element is fed by a different source, two wires (black and purple) that are covered by a loose black wrap. It can be seen near the back of the seat, I just cut away a small portion of the wrap, and I was able to probe the two wires for continuity. If you find that the back element is bad, you could always cut the two wires and butt-splice them together to complete the circuit for the lower element. You won't have any back heat, but your butt will be nice and warm.

I found that all of the wire splices under the seat foam weren't covered in anything, but I decided to heat-shrink the one's that I did to keep it safe. I don't need any fires at this point.

Also, the burnt spot was underneath the leather, on the foam itself. It wasn't visible before taking the seat apart.

Let me know if you want more instruction on which wires to probe to run a quick test, I can try to snap a photo and maybe I'll write up a quick repair procedure for the site.

-Tom

Hello, I lucked out with my 99 2500 Burb. My drivers seat was out so I changed out relays and it still didn't work. After digging into it I found that my back side of my seat, the real little wires that connect the element had came off. I resoldered them but my relay still ended up being bad.

My main question is....where can I get this $ 20.00 relay people are talking about ?

The dealer wants around $100.00 (online maybee $80.00) and I've been to three auto stores and they can't get it.

Thanks for the help.............................................. ...................

This $20.00 relay came from a store called Princess Auto in Canada.A few years back I purchased a couple (GM part #25638146).The Princess Auto part number is 8052288.(six pin relay)You could try on line to see if they still carry this product.[url]www.princessauto.com.Their newest catalogue does not show the product.Let me know how you make out.
chuck's
-

This $20.00 relay came from a store called Princess Auto in Canada.A few years back I purchased a couple (GM part #25638146).The Princess Auto part number is 8052288.(six pin relay)You could try on line to see if they still carry this product.[url]www.princessauto.com.Their newest catalogue does not show the product.Let me know how you make out.
chuck's
-

I emailed them and got this back, Thanks for the info anyway, I guess I'll be going to the junkyards.

Good Day Jim,

I have searched for the item you require but can confirm that it has been discontinued and none of our stores have it in stock.
We apologize for this inconvenience and thank you for your inquiry.

Yours truly,
Annette


====================================
Mail Order
Princess Auto Ltd.
Box 1005
Winnipeg, MB R3C 2W7

Great Thread:

http://cgi.ebay.com/ebaymotors/HEATED-SEAT-MODULE-GMC-25638146_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el 1116QQhashZitem2ea2ddbd3bQQitemZ200300936507QQptZM otorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

GM 25638146 heated seat module
Just look up under the seat under the foam and find this:
http://i7.ebayimg.com/01/i/001/2c/3f/af76_1.JPG

It should click each time you move the heated seat switch from off/low/high

I couldn't find a cheaper one online. Junk yard is next stop...

Very good thread. I appreciate folks taking time to enter what they did. It helped me understand, so I think I will give this a shot this coming Saturday. My driver's side heat is inop. Passenger side works good. After reading about the relay, I did a sound check. In my quiet garage, I simply turned on the ignition and buckled the passenger seat. I hear a definite, muffled click when I move switch from OFF to LOW, but no click when I go from LOW to HI. Btw, this doesn't work if seat belt is not clicked. So I leave it in LOW for a about 1 to 2 minutes and observe my backside is getting warm. Then, when I selected HI, I observed a definite, muffled click and the seat warmed even more. Now over to driver's side that doesn't function. No click when I go from OFF to LOW. I do have a click when I go from LOW to HI...but no heat.
I'm going to pull the seat partially apart this weekend and see if I can incorporate the $0 mod pikappkaz did on 2-2-2008. I'll let you know.