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Heated Seats go off on their own

Pat McDonald

New Member
Joined
Dec 6, 2007
Messages
4
Location
Findlay, Ohio
Hello:

I'm having a problem with the heated seats on my 2003 Avalanche.   You turn on the seats and about a minute later they go off.  

My wife has MS and uses this feature almost year round.   Any ideas? 

Thank you!
 
perhaps this...

JSal69 said:
03-05 Chevrolet/GMC/Cadillac All Full Size Trucks and Utilities Heated Seat Inoperative or Shut Off in 30 Seconds B1825 B2435 B2440 B3606 #PIT3287 - (Nov 23, 2004)

03 - 05 Chevrolet/GMC/Cadillac All Full Size Trucks and Utilities Heated Seat Inoperative or Shut Off in 30 seconds B1825 B2435 B2440 B3606
.

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:

Driver and passenger heated seats inoperative or shut off in 30 seconds. There will be DTCs B2435, B2440, B3606 and/or B1825 set in the Drivers Seat Module. The adjustable pedal position sensor, seat recliner position sensor and both heat seat thermistors share the same 5 volt reference internal to the Drivers Seat Module. A fault in any of these components/circuits can make the heated seats inoperative or shut off in 30 seconds, as well as, the seat recliner and/or adjustment pedals may move in short increments when operated. A fault in either heated seats, adjustable pedal or seat recliner will affect BOTH heated seats.

Recommendation/Instructions:

To help isolate the area of concern use the Tech 2 and go to "Sensor Data" in the Drivers Seat Module. Monitor the following parameters for being out of range:

.

Recline Position - Normal range .39V-4.58V 

Pedal Position (if equipped) - Normal range .39V-4.58V

Psgr. Seat Heat Sensor - Normal range 1V-4V

Drvr. Seat Heat Sensor - Normal range 1V-4V

.

If a parameter is found to be out of range inspect circuits for any opens, shorts to ground, or voltage. If none found, replace the suspect component. Please be aware of the following common areas of concern:

1. The adjustable pedal position sensor internally shorted pulling the 5 volt reference low. Disconnect the adjustable pedal position sensor and see if the heated seats start working correctly, if so replace. NOTE IMPORTANT: The APP ( Accelerator Pedal Position) sensor is NOT the adjustable pedal position sensor. Make sure the correct sensor, adjustable pedal position sensor, is disconnected.

2. The seat recliner position sensor internally shorted pulling the 5 volt reference low. Disconnect the recliner position sensor and see if heated seats start working correctly, if so replace.

3. An open in either heated seat thermistor circuits (signal or low reference). The most common is the passenger thermistor where it passes through seat connector C305 pin "L" or "K" or C399 pins "R" or "G".

NOTE IMPORTANT: The heated seat thermistors act differently to "OPENS and SHORTS" than the adjustable pedal position sensor and seat recliner position sensor. The adjustable pedals and seat recliner sensors can be disconnected for testing of the heated seats. Where as the heated seat thermistor circuit must be working correctly before EITHER heated seat will operate. Disconnecting one thermistor, which may have a concern will not allow the opposite heated seat to work correctly, BOTH side must be operational before EITHER heated seat will operate.

Clearing DTCs

If DTCs will not clear when using the Tech 2 after a repair has been made, try operating the device in which the repair was made. Example, if a repair was made to the passenger heated seat thermistor circuit, the DTCs may not clear unless the passenger heated seat is operated.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

Models:
(03-05 Chevrolet All Full Size Trucks and Utilities) and (03-05 GMC All Full Size Trucks and Utilities) and (03-05 Cadillac All Full Size Utilities)
 
I had mine replaced about 2 years ago.  Mine was the heating element in the back portion of the seat.  My seat would turn off, and sometimes the back part of the seat was SO hot, it felt hotter than the fires of Hell.
 
I am having this problem with only my driver side heated seat. I noticed this ocurred along with my seat not moving automatically. I turned that option off and it stopped the seat from moving. Then came the heat, It also goes off after a few seconds.
The passenger side works. I looked at the info already on this board and don't understand that info.
Can someone tell me if there is a possible fuse I could check for and where I could check for it?
If anyone could tell me in words (not manually described), I would appreciate it.
Thanks,
Ching
 
Must be an ailment going around on the heated seats, mine just went out this past week. ?Have been playing around with mine and found out passenger seat works fine if I don't use the driver's side. ?Hopefully, it just the switch. ?Had an accumilation of snow earlier in the week and when I opened the door to get brush, had a lot of it fall onto my seat and door panel switches.
 
I have the same problem with the driver's seat, but instead of turning OFF, it turns ON, and actually cycles through the 3 levels, then shuts off, then starts over again.

Only seems to happen when it's humid outside (after a rainstorm, etc...)
 
Mine does it too.  I have read that its a short somewhere in the heater element.  YOu need to replace the heater element in the seat.  To do this, you need to remove the seat upholstry and replace the element.  I haven't done this as I don't know where to start and I have leather, so my wife gets a warm arse and I get a cold one :E:  Oh well, maybe someday. 
 
sk8deck said:
Here lately, I swear I think just my back part of my seat is heating up all by itself. But then after while it will stop.

Mine did that the other day and it got wicked hot.  :dunno:
 
I have an '03 and the drivers side will turn on but eventually some sort of safety mechanism turns both heated seats off.  I did experience the drivers seat back element seeming to be "hotter than hell".    Guess its time to rip the seat out and replace the back element.  I wonder if there are any diagrams or books out there on exactly how to do this?
???
 
marzahld said:
I have an '03 and the drivers side will turn on but eventually some sort of safety mechanism turns both heated seats off.   I did experience the drivers seat back element seeming to be "hotter than hell".     Guess its time to rip the seat out and replace the back element.   I wonder if there are any diagrams or books out there on exactly how to do this?
???
Yes

we have lengthy thread about service manuals..

SEARCH for HELM MANUAL you should get some good threads
 
Well... I had the day off yesterday so I decided to run to the dealer and pick up a new seat heater element for the drivers side chair back ($129.00).  It took me about 4 hours to replace it because I wasn't quite sure exactly how to get the seat cover off (they are tight as a drum).   I ended up being able to roll the seat cover up just enough to get the job done because I couldn't figure out how to remove the armrest.     Here's some info for those who might be attempting the same thing:

1. Pull the SIR fuse (airbags) under the hood, and wait 15 min
2. Remove 4 bolts holding the seat track to the truck floor (2 in front, 2 in back).  Don't unhook wires yet as you will need power to slide the seat back and forth as you do this.   The rear bolts can be undone with a 11mm deep socket, the front bolts with a 15mm deep socket (or 5/8 spark plug deep socket if you dont have one as in my case).  NOTE: 2 of the bolts you need to get to are underneath plastic housings so remove these carefully.
3. lean the seat back a little (this will give you more room to work if you dont want to remove the chair back from the seat-- I actually at one point tried to remove my chair back by undoing the 2 bolts, but mine was stuck real good so I gave up)
4. Unhook main wire harness and the 2 wire harness
5. Put seat on tailgate and disconnect the 6 wire seat heater element wiring harness (see picture of my burnt one)
6. Connector is wired as follows:

Black Brown Seat bottom element: Mine measured 4.1 ohm between these 2
Black/R Black/R
Black Yellow Seat back element: My burnt one measured 7.0 ohm between these 2 ( the new one was 4.7 ohm )

7. If you want to save $130 and just get your seat bottom working again, I think you may be able to put a 4.7 ohm resistor in here and then you wouldnt have to take the seat cover off, though I didn't try it.

8. The seat back cover hooks together at the bottom. Insert a long skinny flathead screw driver down the center to unhook the long black plastic strips that are hooked together. 

9. pull seat cover up as far as you can ( a little at a time on each side).  This part required quite a bit of effort on my seat. 
10. At this point you will have (barely) enough room to remove the old element that is stuck to the padding and put in the new one.  For the new one, I recommend sticking the bottom taped end down first, then roll the element underneath the seat cover until the top taped end is in

11. If you've gotten this far, putting it back together is self explanatory.  When putting the seat back on put all bolts in loosely first to ensure good alignment then tighten them down.

While I had my seat out I also put some 3in1 oil in the seat belt spindle since it has been making squeaking noises for the last 6 months  :)

 
My drivers seat did the turn on and cycle thing. It would never stop and the back of the seat would get wicked hot. I took it to the dealer and they said the element in the back of the seat would need to be replaced, it had burned thru. After agreeing to the $300 charge, they called back and said it still was broken even after replacing the element. So they agreed to replace the sensor as if it was under warranty since it is a 2005 and had just gone out of warranty June of 2008 and this was Dec. 2008, plus it has less than 30,000 miles. So they replace the sensor and I go back to pick it up and they tell me they had to replace the seat heater switch also. As I drive away, it starts all over again, heating up and cycling thru settings. I take it back and they can't figure out what is causing it, they've replaced everything. So I remind them it happens when I move my seat and they sit and play with the seat and it starts cycling. This is the first time they've actually seen it do it. They kept it for a week coz they said it was a bad ground somewhere. Turns out the window switch was bad. The seat switch on the door ran thru the window switch and that was where the bad ground was. They replaced that switch and no more seat problems. On the down side when I adjust my windows when the lights are on they dim. According to the dealership this is a quirk with the new switches...  At least my seat works, I have a bad back and need it big time. Plus I only paid $300 for three trips and lots of labor and parts! Can't beat that!
 
My heated seats still work after replacing the drivers side seat back element in '08, however.... I am now feeling the "fires of hell" in my drivers seat bottom...  I am wondering if this is going to be my next repair project?    uggghh..  Removing the seat covers is not fun...  I wonder if the bottom cover is harder than the top?
 
Well,  this became a self fulfilling prophecy for me... The bottom element is now shot.  I know the top is good cause if I select back heat only, everything works....
I guess these elements really aren't designed for long life...

I measured the burnt one out at 3.7 ohms... Considering a new one reads around 4.7 ohms,  I'm now no longer sure if its possible to tell if the element is faulty or not by measuring its resistance...  After removing the bottom seat cover  it was indeed burnt to a crisp!  I found a new one on ebay for $70... 

Well... since I've removed both already, I can say with certainty that the bottom element sure is easier to replace than the top!






 
The new element arrived today, and I measured it at 2.2 ohms...  I'm pretty positive now that no conclusions can be made about these elements by measuring resistance, other than if it is completely short or open....  Maybe if you tried to apply power and measured current you would get somewhere but this is more of a pain to do without making some sort of extension harness...

The new element was a Dorman brand aftermarket part.  I put it all back together and my seat is nice and toasty again.  Just in time for the snow that is coming...  The bottom cover is definitely harder to put back on than it is to remove. 

 
badboy2 said:
how do i disable the heated seats?i just want them off my driver seat at least.

Pull the fuse? both seats are on the same circuit, you'd have to do a bypass to make only one side wrok
 
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