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Heated seats control

MellyVan

Full Member
Joined
Mar 8, 2013
Messages
103
Hi,

My heated seats controls for the drivers seat flick the heaters on and off each second, then after a while it stays on and when I try to put it off, it flicks on again. Totally irregular behaviour. Buttons on door still work though, but the car has a mind of its own concerning the heat of my seat :)

Now, the real question:
Does anyone have wiring info on door module to relay?

I hear a relay clicking when the heaters switch on, where is this relay? Which one is it? Can anyone supply me with some info!?
 
That relay is soddered to a control board under the seat.  Mine did the same thing and eventually got to where my seat heater would stay on. I cant stand them and never used them any way so I removed the relay from that board. Un soldered it. The control lights still flicker on and off but it does nothing and that does not bother me. I also removed the heating pad from the bottom of the driver seat it was burnt.
 
Mm, I definitely hear a relay clicking under neath the dash, left part of it under the steering column somewhere...

The seat heater in the back still functions, and I use this feature a lot in winter time, since it gets cold here (already is).


I've jumped to the conclusion that the fault lies somewhere, which probably can't be found. What I want to do is unhook the lights/controls in the door, unhook the original relays, and make my own relay and switch where I can control the heater with.

I need wiring of under seat wires and door module to do this. Anyone that can be of any help in this?
 
see if any of those help you ... you might not be able to just disconnect them because of other things on the same circuit (power pedals seat memory and etc) it sounds like what they are saying on those other forums that the module might need reflashed with a software update or the module needs replaced and will need programing

http://www.justanswer.com/chevy/1d15l-driver-s-heated-seat-comes.html

http://www.gm-trucks.com/forums/topic/89249-heated-seats/

http://chevroletforum.com/forum/silverado-fullsize-pick-ups-21/drivers-side-heated-seat-turns-itself-37318/
 
AV 2500 said:
Yea that would help mine is an 03 if yours is a 07+ my experiences is useless.

I work at a chevy dealer, i have access to all the diagnostics. With a model year, i can direct him to the correct fix.
 
there is a TSB about something similar:

Subject:  Intermittent Heated Seats Inoperative, DTC B3941 Set (Reprogram Driver Seat Module)
 
Models:  2003?2005 Cadillac Escalade, Escalade ESV, Escalade EXT 
2003?2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe 
2003?2005 GMC Sierra, Yukon, Yukon XL, Yukon Denali 
All with Seat FRT, Individual (Non BKT) (RPO AN3)
2003?2005 HUMMER H2 with Seat, Front Bucket Deluxe (RPO AR9) 

--------------------------------------------------------------------------------

Condition:
Some customers may comment that occasionally the seat heater will not operate when activated. If the ignition key is cycled OFF and back ON again, the heated seat will operate correctly. Also, on some LB7 diesel engine vehicles, the seat heater may turn itself off during the first 10 minutes of operation. This occurs only with the first activation for the day and works correctly with subsequent activations immediately after the event. These conditions are intermittent and DTC B3941 may be set.

Correction:
Technicians are to reprogram the driver seat module with an updated software calibration. This new service calibration was released with TIS satellite data update version 6.5 available June 13, 2005. As always, make sure your Tech 2? is updated with the latest software version.

 
And another:

Subject:  Heated Seat Inoperative or Shuts Off In 30 Seconds
 
Models:  2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT 
2003-2006 Chevrolet Avalanche, Suburban, Tahoe
2003-2007 Silverado Classic
2003-2007 GMC Sierra Classic, Sierra Denali Classic
2003-2006 Yukon, Yukon Denali, Yukon XL, Yukon Denali XL 
2003-2007 Hummer H2

--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this 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 heated seats, adjustable pedal or seat recliner will affect BOTH heated seats.

Note:: Even if the vehicle is not equipped with adjustable pedals DTC B3606 still may set.

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".
 4. A chaff to ground on either heated seat thermistor signal circuits. The most common is circuit 5475 black/red or dark blue shorted to ground in the passenger seat near the buckle.
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 diagnostic or repair 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.
 
And yet another, altho i doubt this is your issue:

Subject:  Drivers or Passengers Heated Seats Turn on By Themselves
 
Models:  .
   

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.


--------------------------------------------------------------------------------

Condition/Concern:
A customer may comment that the front passenger or drivers heated seats turn on by themselves. Dealer technicians my not be able to duplicate the concern and no DTCs will be set. This concern maybe caused by the customer inadvertently contacting the heated seat switch.

Recommendation/Instructions:
To correct this concern, a new low profile switch has been released. The new part number switches are as follows:

15116861 passenger

15116862 drivers w/ memory, heated, and adjusted pedals

15116863 drivers w/ memory and heated only

.

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. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:(03 and 04 Chevrolet Silverado) and (03 and 04 Chevrolet Avalanche) and (03 and 04 Chevrolet Tahoe, Suburban) and (03 and 04 GMC Sierra, Sierra Denali) and (03 and 04 GMC Yukon, Yukon XL, Denali, Denali XL) and (03 and 04 Cadillac Escalade, EXT, ESV)

 
Description and operation:

The driver and passenger heated seats have 2 heat zone operating modes with 3 heat level modes and will operate only while the engine is running. The heat zones are determined by which of the 2 heated seat buttons are pressed, while the heat level is determined by the number of times they are pressed. Pressing the seat cushion button 1 time will activate the seat back and cushion heater elements in the high mode. Each time the seat cushion button is pressed the seat back and cushion heat level is reduced from high to medium, low, and off. Pressing the heated seat back button 1 time will activate only the seat back heater element in the high mode. Each time the seat back button is pressed the seat back heat level is reduced from high to medium, low, and off. During heated seat operation the heat zone operating mode may be changed without affecting the current heat level mode.

The heated seat switches are momentary contact switches and are inputs to the driver and passenger door modules. Battery voltage is supplied to the switch assembly from the door module, and when a heated seat switch is pressed and released a brief switch signal voltage is supplied to the door module. Whenever the door module receives an active heated seat switch input, the next heated seat operating mode is determined by whatever the current mode may be. The seat heater elements are controlled by the driver seat module using inputs from the door modules through Class 2 serial data circuit messages. The driver seat module controls the voltage supply and the ground circuits to the seat heater elements. When a heated seat function is commanded active, the seat module will switch battery voltage to the heater element supply circuits, and ground is provided through low side drive control circuits. During heated seat operation both the seat back and cushion heater elements are supplied battery voltage. The seat module grounds the appropriate control circuits for back only or back and cushion heating modes, and opens or closes the active control circuits as necessary in order to maintain the desired seat temperature. The seat module relies on inputs from thermistors located in the driver and passenger seat backs to control heated seat temperatures. The thermistors are 2 wire sensors supplied with a 5-volt referenced signal circuit and a low reference circuit from the seat module. Resistance through the thermistors varies with temperature causing the heated seat sensor signal circuit voltage levels to decrease as the seat back temperatures rise. The seat modules allow heated seat operation only while the engine is running which is determined by a Class 2 serial data circuit message from the powertrain control module.
 
I think its the module... if the element is bad it usually doesnt turn back on by its self which is what he is reporting his doing  (y)
 
@wyotonka: thanks, mine is an 03 indeed.

@krazycarguy: thanks for your effort!!

1st TSB: it does this every time, and cycling the key to OFF and ON again and again doesn't ever solve it, so not for me
2nd TSB: it doesn't shut off in 30 seconds, it keeps intermittently change mode but is on almost the whole ride (every ride, 5min, but also 30mins)
3rd TSB: i'm not touching the buttons myself :D

As for the description and operation:
It is going to be hard to figure out what this is causing. Which wire from the the heated seat controls in the door gives signal to the door module? I'll have to disconnect this and see if the seat heater remains of this way, then I have found my problem.
 
My driver's seat was doing this exact thing last fall.

My research at the time pointed to burned out heating units as a common cause.

Something to do with the resistance of a burned out heater pad and current draw or something like that causes the control circuit to cycle sporadically.

Here are some pictures of my burned out heating units.

The unit from the seat back, which is actually smaller than the one in the bottom portion of the seat:





Here is my old bottom portion seat heater pad:



The bottom heater was not burned out, but I had ordered both heater pads and just went ahead and replaced them both.

It had been reported that the seat back heater pad is more likely to burn out than the bottom heater pad.

That was also the case in my instance.

After I replaced the heater pads with Dorman replacement units, my seat heaters starting working as expected and have ever since.
 
wyotonka said:
I think its the module... if the element is bad it usually doesnt turn back on by its self which is what he is reporting his doing  (y)

Actually, mine did until I performed the repair in the previous post.
 
If i could post up the diagnostic flow chart i would, but i cant figure out how to do it so its readable for you, lol. What I would do if i were you, unplug the heater element and check resistance. Should be 1.5 - 5.5 Ohms. They are two wire plugs, under the seat. If not in spec, replace.
 
krazycarguy said:
If i could post up the diagnostic flow chart i would, but i cant figure out how to do it so its readable for you, lol. What I would do if i were you, unplug the heater element and check resistance. Should be 1.5 - 5.5 Ohms. They are two wire plugs, under the seat. If not in spec, replace.

The plugs for the heater elements are under the seat.

I suggest taking the seat out of the truck.

It's not that hard to do.

I used this set of videos from The Seat Shop to help me disassemble and reassemble my seat when I replaced my heater units.
 
There are some 10 plugs and connectors under the seat. Which one should I disconnect?

Forgot to mention: My drivers bottom heater hasn't worked since I bought the truck last year. But it hasn't been behaving like this before... Can I unplug the bottom heater and see if that works out for me?

@Krazycarguy: the module only has some six wires if I remember correct, do you know which are for the heater controls? If i disconnect these, I know if the module is causing it, or simply displaying the erorr another component is making.

Thanks!
 
Sorry I don't have a better picture showing the plugs for the seat heaters, but here is the best one I do have:



It's has been about a year since I worked on these, but I do seem to remember the wire pigtails for both of the seat heaters come from the right hand side (the side closest to the centerline of the truck, next to the console) and at least the seat back heater had possibly TWO connectors, as can somewhat been seen in this picture.

One of the connectors was at the end of the line while the other one poked out several inches back up the length of the harness.

You are correct, there are several wires and connectors under the seat for everything from the seat heaters and the side air bag and seat adjuster motors to the seat belt connected switch.

The connector for the air bag is the easiest to spot since it is the only one of it's color and it has a special retainer pin that has to be removed in order for you to disconnect it.

The main connector between the seat and the truck is like any other large connector and shouldn't give you any problems if you decide to take the seat out of the truck.

And like I said before, I would plan on removing the seat as that makes it so much easier to run down all of those wires.

If I am remembering correctly the connectors for the seat heaters all hook up right about in the center area of the seat bottom.

I can't even see that spot with the seat in the truck.

I also remember comparing the resistance between my burned out elements and the new replacement elements using my digital multi-meter and the difference wasn't enough for me to tell one from the other.

I found that surprising given the amount of damage on the burned out seat heater pad.
 
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