Cadillac Repair/Heated seats

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QUESTION: Heated seats front and rear just stopped working. All the switches light up as should. All the fuses and relays are good. This may or may not have happened after I disconnected and reconnected the battery. I don't think all the elements in the seats can go bad at once and if they did I should play the lottery. Something must be causing these seats to not work all at once. No codes. There has got to be one main source that sends a signal to all the seats. I don't buy that this is a individual seat problem because they all went out at once. 2000 Deville.

ANSWER: Hello,

First, when you checked all fuses and relays, did you check to see how many fuse boxes are in the car? They commonly have two and sometimes three. You owners mnual will give locations.
get back to me.

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QUESTION: Everybody I talked to said the power that runs the modules comes from the rear fuse box. HTDTSLF FUSE 10 amp and IGN3 Fuse are the power sources and they are good. Relay 59 I believe also in that box is part of it and that is good. My gut feeling tell me that the problem is not in the fuse box.I came home from work last night and the heated seats were in fact working. Started car in the morning and they didn't work. This don't make any sense.

ANSWER: Hello,

This is strange where you had no issues until you disconnected and reconnected.The battery. Although you did not tell me why you did that in the first place.

Now it appears that from non-working, we have gone to intermittent.
Now, I do not want you changing parts on my suggestion, but it is worth considering.
When dealing with electronics and intermittent issues, I consider the main source. In this case, there is either a module that supplies power to all the seats involved, or this event is covered through the BCM (body control module).
My thought here of which I have run into would be a cracked circuit board. You drive down the road possibly hitting a bump and the crack goes back together. Then you drive the car more and the circuit board separates.
From your description, which appears to be very well thought out, would be consistent with such an event.
I have run across this in older vehicles exposed to temperature changes, bad roads etc, very commonly on dash and heater control situations.
The other possibility would be a broken power wire inside the plastic sheathing.
That was extremely common in the old VATS anti theft system, however that wiring was around 22 gauge of which was very thin, and you are not dealing with thin wiring such as that for your seat power, which may be a 12 gauge wire.
That is the only two scenarios that I can think of.
Again, you did not state why the battery was disconnected in the first place.
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---------- FOLLOW-UP ----------

QUESTION: Thank you for taking the time to try and diagnose my problem. I disconnected and reconnected the battery because I am getting a C1252 and C1253 (C1252 Left front normal force malfunction and C1253 Right front normal force malfunction )code that doesn't go away when you clear the codes from the dash. This is the ABS module that is connected to the ABS pump EBTCM = Electronic Brake and Traction Control Module. Probably a bad module or bad connection. Anyways after one last clutching at straws move I disconnected the battery again and touched the negative and positive cables for 30 seconds to clear all memory. Guess what the seats work again. A mechanic friend of mine said I hit a million to one shot as probably the same way I disrupted the modules when I disconnected the battery they somehow reset when I did it again. Sort of like rebooting a computer. Why the heated seat modules reacted this way when I originally disconnected the battery is anybody's guess and we will never know, but they work now!

Answer
Hi,

The first problem is that you did what is not supposed to be done, trying to knock out the codes by disconnecting the battery with an attempt to reboot the system. That is not the correct way to clear the codes.
The code you can't get rid of is known as a hard code. A hard code is a code you cannot remove unless the issue is fixed. GM for years had problems with their brake anti lock controls modules. I never ran across a problem though that ever affected the braking. The modules were severely over priced at $500-$1,500, for what? To remove a code because of a design flaw?
The codes come on for a reason and by disconnecting the battery, all you are doing is prolonging the issue until the next time the code comes on.
A tech II scanner that many garages have or equivalent isolate the problem that caused the code to come on in the first place, the specific failed part us replaced and the scanner is used to erase the code.
See,these are known as diagnostic trouble codes (DTCs).
Your 1262 and 1253 normal force modules for right and left are not telling you what is causing these codes to appear. The scanner tells you the exact reason.
So, in other words, you have not fixed anything and these codes will reappear in short order and disconnecting the battery may create another problem other than the heated seats.
Part of my problem trying to diagnose a problem is that the questioner hasn't told me what went on before they had a specific problem.
Had I known that you disconnected the battery to remove codes, obviously I would not have told you of a effective circuit board. That is why I asked you why you disconnected the battery.
These vehicles are not Luke the old cars that didn't have computers. Some alley mechanic is simply not capable of fixing them anymore. The worst place to go is a dealer. Most of them are parts changers until there is no money in your wallet and they still never fixed the problem.
Sometimes in the long run, it is cheaper to go to a reputable garage with the skill and equipment to fix the vehicle correctly in the first place.
Here is another warming about disconnecting the battery.
GMs are better than Ford's on this issue, but if you disconnect the battery for a period of time, you might find the engine will crank when reconnected, but won't start. That would be because you just list the memory in the computer for the transponder (chip in the key). When that happens you have two options: either tow the vehicle to a dealer and get ripped off at $150.00 per new key and programming, or have a locksmith come out and do the same thing for less.
I am glad this all worked out for you,but now you realize just how complicated these vehicles are.

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Rob Painter

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Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?

Experience

Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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