Troubleshooting Heated Seat


stuzman
10-16-2005, 05:47 PM
Since I had some free time today, I decided to look into why the driver's side seat wouldn't heat on my 2000 Buick LeSabre Custom. I hooked up my Tech 2 scanner and looked to see if there was an input to the driver door module (DDM) from the heat switch. No problem there. I decided to look at the rear integration module (RIM) to see if it was receiving an input from the DDM for the request for heat. That looked okay too. Next was looking at the dash integration module (DIM) to see if there was an output for the load management to the RIM. The default load management is zero (0), and since load management 1 and 2 were disabled, I knew this section was okay. Then I looked at the input to the RIM to see if the heated seat module gave the okay for its heat status. At this point the heated seat module wasn't sending an output for a heat status signal. Since the RIM did not receive this signal, the RIM would not send an output signal to the DDM to toggle the LEDs in the heated switch on each press of the button. So I knew the problem was with the heated seat module or with the load (heaters).

The heated seat module is located directly under the seat. In fact it's bolted under the seat with two screws and has two connectors. I found it easier to get the seat all the way back and take out the module to gain access to the connectors. The connector on the right facing the unit from the front while it's bolted has two gray wires (thermistor), one black and one red wire. The black and red wires are for the heaters (two heaters wired in series). I put an ohmeter across these wires and found the heater circuit open. Great! Now I have to tear into the seat. I went ahead and checked the resistance of the thermistor and found it to be okay. Since I had the module out I decided to open it for a visual inspection and checked a few transistors, diodes, etc. and all of that looked okay.

So, at this point there is an open heater (not sure of which one since there is one in the back of the seat and one for the seat cushion). Of course, the worse case would be that both of them are open. There wasn't a separate connector for each heater to isolate the culprit.

For some preliminary steps for someone who has this same problem, there is a relay in the heated seat module which one can hear (energizing) with the press of the heated seat button from an off position to a high positon. This relay will only click once and will not be heard when going from high to low (makes sense, it's already pulled in). When the switch is pressed again to go off, the relay can be heard again which is deenergizing. This is a normal operation.

In my case, the relay could be heard on the first press of the button when going from off to high and then would drop out within a second or so. Even if you hold the button in, the relay will still drop out. This relay has nothing to do with supplying power directly to the heaters. A solid state device is used for that. This relay sends an output (high to low) of its heat status across a wire (not networked) to the RIM saying that the module is working. In other words, the load (heaters) are monitored for current flow. So, if the heater(s) are open, then the relay won't stay pulled in and no message to the RIM signifying this.

Other symptons are the LED for the heat switch would stay on High with no heat. Pressing the button again would not go to Low unless you repeatly pressed the button. I could never get it to go to Off until I turned the igniton off.

All of the above modules communicate between themselves over the Class 2 network with the exception of the heated seat module. The RIM communicates with this module over two hard-wired connections for a heated seat switch signal and a status output.

Hopefully, some of this information can help someone out with a similar problem. Usually, the problem is open heater(s) which are easy enough to check or a heated seat module.

jase386
10-19-2005, 11:53 AM
Keep us posted if you decide to journey into the seat cushions to find those heaters. ive noticed a big zipper in the rear of my drivers seat, and have wondered if it is there, for the sole reason of working on the heaters.

stuzman
10-19-2005, 03:27 PM
Keep us posted if you decide to journey into the seat cushions to find those heaters. ive noticed a big zipper in the rear of my drivers seat, and have wondered if it is there, for the sole reason of working on the heaters.

If you like I can send you the part of the manual which entails about taking the seat out and replacing the heater(s). You have your settings to not receive e-mail. Just let me know...

jase386
10-19-2005, 03:59 PM
i have updated that, thanks for all of your help. email should go thru now

jase386
10-25-2005, 08:55 AM
Stuzman, are you there?

email me anytime.

gerhardm
10-06-2006, 12:37 PM
If you like I can send you the part of the manual which entails about taking the seat out and replacing the heater(s). You have your settings to not receive e-mail. Just let me know...

I have encountered the exact same problem with the heated seats on my 2002 LeSabre. Can you send me the part of the manual which entails about taking the seat out and replacing the heater(s)? Appreciate your help.

G

BNaylor
10-06-2006, 12:41 PM
I have encountered the exact same problem with the heated seats on my 2002 LeSabre. Can you send me the part of the manual which entails about taking the seat out and replacing the heater(s)? Appreciate your help.

G

Sorry this thread is too old. I recommend that you start a new thread/post.

Thread closed.

POSTING IN CLOSED OR OUTDATED THREADS:
If a thread has been closed, there is probably a logical reason for it. If you feel that the reason(s) for closure of the original thread are unjustified or wish further clarification feel free to contact any member of the moderating team. However, do not start a new thread about another closed thread.

Please avoid posting or voting in outdated threads. It merely clutters up the message board and makes it more difficult for fellow members to sort through the vast amount of information contained on the boards. If you have new and important information to add regarding a past discussion, feel free to start a new thread and if need be, add a link to the original thread.

Add your comment to this topic!