2001 Cadillac Seville SLS malfunctioning DDM

The good part about your vehicle, is all of the door modules are the same part number. This would isolate a faulty one, if you swap with another door. If your problems follow, then it is the module. These are plug and play modules, there is no programming involved. If you are confident in removing a door trim panel, then you can perform the task. What are the symptoms that you are being faced with?

I will get back to you as soon as I can. I m currently at work, and can't take the time to process your info. I am not suspecting a module fault, but like I say, need to process the info, and do some research.

In an attempt to decipher the information that you posted, I will address some things, and I may require more information, in an effort to help. Aside from the heat/ac, and heated seat issue, you mention changes that occur when you press #1 or #2. Changes are going to occur, and this is a normal part of personalization settings. The reason the heater shuts off, and the radio comes on, is that I believe when the #1 memory was set, the heater was probably off, and the radio was on. And likewise, a different set of parameters was stored when driver #2 memory was set. To test this, make some changes to the heater, and radio, and go through the procedure of storing them for a specific driver. Change between 1 and 2, and see if the changes you made, are the ones that appear for each respective position.

You say that the heated seats, and the heater stop working at the same time. Lets talk first about the heat/ac. In taking a long time to come on, does that mean that the display is on, the fan is blowing, and there is just no warm air emitted from the vents. Give some specifics on this. When you are experiencing a fault in operation, what is happening? What does the display do, is it(display) responding to temperature changes with the ****, mode changes with the buttons, and is the fan operating? Take into consideration, that the system may not run the fan for a bit of time, if the engine is started stone cold, and you are requesting heat. If the engine temperature is stone cold, then it knows it can't accomplish a heat request. It should come on as the temperature increases a bit.

The heated seats, does both the driver and passenger work, and not work at the same time? Does the switch indicator turn on and respond to pressings(e.G. Hi/Med/Lo), when the heated seats are non-functional? If it does, listen at the front of the seat bottom cushion, when the heated seat is first cycled on, in fact you can also do this when it functions. You will hear a relay click inside of the heated seat module. If you can key in on this click, take a mental note. If you hear one click when turned on, I would assume that the seat heater is going to warm, verify that. If you hear one click, and then a second similar click shortly after, the system has shut back off due to over-current. This is key to determining if you have a heated seat problem, which all Cadillac K bodies(Seville/Deville) did, in the early 2000 models.

Lastly, you have the capability on your vehicle, of performing a preliminary check that only a scan tool like the Tech 2 is capable of, that is getting trouble codes from modules that other scanners can't. You will need a writing utensil, and some paper to record the codes, and record all of them. Start by turning the key to the 'on' position. Press and hold both the 'info' button upward, and the 'on/off' button together. After a few seconds of holding, all the display segments will light, and you can release the buttons. Your info center will display 'ALL?', Press the 'on/off' button again. The display should now read 'ALL CODES?', And press the 'on/off' button again. The system will display codes for all modules(that are communicating) in alphabetical order by module. The reason I say 'that are communicating', is that if a module is not communicating, you may not even see it on the list of availables.

Get as much specifics on the faults, that you can gather. Record codes and reply to this post.

First of all, thanks for the info. I will see what I can offer, but this long distance relationship format, can limit some abilities. I consider automotive repair and troubleshooting, more of a hands on affair.

Just an FYI, any code with U prefix is a communications fault code. It appears as though none of these have any relevance.

So, looking at the most recent info, it appears that the concern only affects heat/ac, and heated seats. I don't know if you have checked, but does this make both front heated seats inoperative, or all four(front/rear). The heated seats are pretty much their own system, with a little influence from the rear integration module, to inhibit operation when low voltage permits load shedding. I looked at the service information, for some common ties between the heated seats, and AC operation. Coincidentally there are some ties, that could suggest a power loss problem. All four heated seat modules are supplied ignition power from the IGN 3 RR fuse in the rear fuse block, and without ignition power to the modules, it looks like the switches will be inoperative, all four. Looking at the distribution of this fuse, it also feeds power to the instrument panel module(A/C control head), and to the level control system. You may not even know if the level control system is working or not, there is no visual indicator. This IGN 3 fuse is powered by the IGN 3 relay. This elay also supplies power to the HVAC fuse, and the ABS fuse. This is where the two systems would tie together mostly, in my opinion. The kicker, and the information I have yet to locate, is what this ignition feed to the ABS system does, and why you don't either have an ABS code, or a light that comes on.

The HVAC fuse supplies power to all the actuators, mode/temp, and auxiliary(rear), as well as the auxiliary control head, so check it also. Is it blank when you are having the other symptoms?

Here is what I would look at, and what I would suggest as a preliminary. First, if the symptoms are not present, remove the IGN 3 RR fuse from the rear fuse block, and run a check to see what happens. If all the symptoms that are present with only that fuse removed, are exactly the same as the ones you are getting, that would suggest a power problem from that circuit. Possibly a poor connection from the fuse block itself.

If the symptoms are not exactly the ones you see intermittently, then reinstall the fuse, and then remove the IGN 3 relay. Re-evaluate the symptoms from there, determine if they are exact. If they are, swap that relay out, with another of similar look/number. There should be a few in that fuse block tha could be swapped for test purposes. Re-evaluate after that. If the symptoms no longer appear, you have a faulty relay. If the symptoms do appear, this could suggest that you possibly may have a faulty ignition switch. It would have to be verified, that power and ground are not present to energize the relay, prior to condemning the ignition switch.

I will attach for you, the schematics that I am referencing. Hopefully, we can keep it basic, and have a faulty relay.

Another note, if we are to suspect an ignition switch, look at those other relay feeds in the schmatic, and check for symptoms wit those. Things like the park brake release, whether or not you can shift from park without applying the brake, rear defogger work, etc.

Since the HVAC fuse is supplying power to only the actuators, it would seem to make sense that you would have HVAC system concerns at the same time as heated seat concerns. Since the rear HVAC control head is out of visibility, when the symptoms are occurring, take the extra step and see if the rear head is also working. I currently have a 2000 STS that I checked by removing the fuse. The heated seat switches for the front were inoperative, but the HVAC seemed functional.

Also, on the car that I have, I removed the IGN 3 relay(#49), and immediately the ABS, red brake warning indicator, and TC icons illuminated.

Is the car currently in freezing temperatures, to where the cables could be frozen in their sleeves. I know of no other way of releasing the park brake, if the manual release don't work, other than cutting the main cable. If the reason it is not releasing, is it is stuck in the cables, you should be able to pull up on the pedal when the manual release is activated.