carl425 Posted February 18, 2006 Report Share Posted February 18, 2006 Okay my drivers side seat heater isn't working and hasn't for a while. I never used it Florida but now that we're in Germany I'm a little more inclined to get it working. So, I started by pulling the relay/control unit out. I drilled out the rivets and while disconnecting one of the three connectors noticed that one of them was routed so that the wires went between teh seat spring and teh cushion. When I got the unit all the way out I looked and one of those wires was chaffed to through the insulation to the copper. I grumbled about the dealership mechanic who last worked on the seat and routed the wire that way (no offense to any dealer mechanics to may frequent this board but I've had some BAD luck in the past...) while I cut and spliced the wire and heat shrinked the connection. Thinking I had the problem licked, I reinstalled the relay/control unit and it still didn't work. I pulled the back seat out to get to the fuse for the seat heaters and the fuse was good (I tried a new spare just t be sure). I think it's working on low but it could have been my body heat too. Any of you with these seats know that there's no doubt when it's working on high though. SO, my question is, could the chaffed wire have caused the relay to go bad (or maybe just the HIGH circuit) and how do I test it? I pulled it apart when I had it out and everything looked good inside. No loose or broken solder connections or any "burned" spots. If the relay is good, how do I check the element(s) in the seats? If I had a schematic I could see which terminals on which connectors go to the elements and do a continuity check, right? Also, I thought the bottom and the back were two different circuits, so if neither are working, wouldn't that point to the relay/control unit? Thanks to anyone who spent the time to read this, and double thanks in advance to anyone who can help! Carl P. Link to comment Share on other sites More sharing options...
JimD Posted February 18, 2006 Report Share Posted February 18, 2006 Let's hope your '99 and my '98 are the same!! The Heated Seat Module powers the seat cushion element and the seat back element in series. Check for seat back element continuity between the pins of the two pin connector (C3). Check for seat cushion element continuity from A (red) to B (black) pins on the four pin connector (C2). There is also a thermistor in the seat cushion for temperature control. You should get some resistance from C (gray) to D (gray) on C2. On the 8 pin connector (C1), you should have battery voltage on B (orange) and ignition switched battery voltage on A (brown). Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
WarrenJ Posted February 19, 2006 Report Share Posted February 19, 2006 This is from a 1995 FSM, so it may differ from yours. Nonetheless, Cadillac has tended to use the same approach across model changes. Maybe it will help point you in the right direction. http://i7.photobucket.com/albums/y299/WBucket/SeatHeat95.jpg (239KB) Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
carl425 Posted February 19, 2006 Author Report Share Posted February 19, 2006 This is from a 1995 FSM, so it may differ from yours. Nonetheless, Cadillac has tended to use the same approach across model changes. Maybe it will help point you in the right direction. http://i7.photobucket.com/albums/y299/WBucket/SeatHeat95.jpg (239KB) Regards, Warren Thanks a heap, Warren! I am bidding on a FSM for my 99 as we speak so hopefully I won't have to ask ya'll to dig up any more info for me anymore, if I win it. ;o) Jim, thanks for your info too. I'm going to try and shoot the wires this afternoon after church so we'll see what I find. Carl P. Link to comment Share on other sites More sharing options...
WarrenJ Posted February 20, 2006 Report Share Posted February 20, 2006 I think it's working on low but it could have been my body heat too . . . . Any of you with these seats know that there's no doubt when it's working on high though. Yup, "hot cross buns" there. Just the same, if it's working on "LOW," you *will* know about it. No ambiguity involved. If you're uncertain whether or not it's working on "LOW," it ain't! Please let us know if you enjoy success and, if so, how. That is the sort of info that is most valuable to the folk here. It's how we help each other. Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
carl425 Posted February 20, 2006 Author Report Share Posted February 20, 2006 I think it's working on low but it could have been my body heat too . . . . Any of you with these seats know that there's no doubt when it's working on high though. Yup, "hot cross buns" there. Just the same, if it's working on "LOW," you *will* know about it. No ambiguity involved. If you're uncertain whether or not it's working on "LOW," it ain't! Please let us know if you enjoy success and, if so, how. That is the sort of info that is most valuable to the folk here. It's how we help each other. Regards, Warren Warren, I don't suppose your wealth of knowledge exteneds into the arena of the speed limiter too, does it? I was on the way back from the airport today and I had the crusie set at 100 and this Mercedes comes floating by and I, of course, couldn't have that. So I sped up and got next to him. He knew what was going on and when we both floored it, I took him easy up to 130 and I got the old "TOP SPEED REACHED-FUEL LIMITED" Argghhh! He just kept going and it felt like I hit the brakes. This is obvisouly unacceptable and must be remedied. It was still pulling like a mule when it happened too making it that much more irritating... CRP Link to comment Share on other sites More sharing options...
carl425 Posted February 20, 2006 Author Report Share Posted February 20, 2006 Let's hope your '99 and my '98 are the same!! The Heated Seat Module powers the seat cushion element and the seat back element in series. Check for seat back element continuity between the pins of the two pin connector (C3). Check for seat cushion element continuity from A (red) to B (black) pins on the four pin connector (C2). There is also a thermistor in the seat cushion for temperature control. You should get some resistance from C (gray) to D (gray) on C2. On the 8 pin connector (C1), you should have battery voltage on B (orange) and ignition switched battery voltage on A (brown). Okay, I went out and shot the wires and this is what I came up with. There is continuity for both the seat back and the cushion and there is power at the orange (constant) and brown (switched). However, I didn't get any resistance when I checked the two gray wires on the C2 connector. Does this mean the thermistor is bad? If so, does anyone have a good P/N for it? Also, I turned the seat heater on and it supplies power to the seat cushion. There is 4.8 volts to one of the gray wires on the C2 plug and 11.8 to the red wire. So does this mean that since the termistor isn't working that the control unit doesn't "see" a complete the circuit for the cushion and therefore doesn't heat the cushion nor the seat back? I'm hoping to not have to tear into the seat cushion, but if I have to then I will. Gotta get her fixed! Link to comment Share on other sites More sharing options...
JimD Posted February 20, 2006 Report Share Posted February 20, 2006 Sounds like the thermistor is open. I would patch in a 1K or some slightly higher common value 1/2 Watt resistor in the two gray wires to complete that circuit for testing purposes only. Be aware that the thermistor is intended to provide feedback to the module for temperature control. I have no idea if GM carries a part # for the termistor but I doubt it. You might have to pull the seat cushion apart to see the color coding on the part and find a replacement based on value. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
WarrenJ Posted February 20, 2006 Report Share Posted February 20, 2006 I don't suppose your wealth of knowledge exteneds into the arena of the speed limiter too, does it? I was on the way back from the airport today and I had the crusie set at 100 and this Mercedes comes floating by and I, of course, couldn't have that. So I sped up and got next to him. He knew what was going on and when we both floored it, I took him easy up to 130 and I got the old "TOP SPEED REACHED-FUEL LIMITED" Argghhh! He just kept going and it felt like I hit the brakes. This is obvisouly unacceptable and must be remedied. It was still pulling like a mule when it happened too making it that much more irritating... You can look in your driver's door jamb and see what speed rated tires were supplied on the vehicle when it was first purchased. Your car will be speed-limited to 115mph or 130mph depending upon which tire type it was originally equipped with when it left the factory. Only if it left the factory with "Z" rated tires will it not be speed governed. And no, there is no work-around for this. In your case, 130mph is all your car will ever see. Sorry. Regards, Warren P.S. If I was doing 130mph I don't think I'd have had time to look at the DIC. Ah youth . . . . There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
stefank Posted February 20, 2006 Report Share Posted February 20, 2006 I think there is a workaround...but this would be definiteley illegal...I have the same issue with my Seville SLS, at 220 kph it is top-speed limited although it came with Z-tires from the factory (and still has Z-rated tires on). If one would use a signal-divider (expression?) which cuts every, say, nineth speed pulse from the speed sensor in the tranny, the computers would think the car is 10 % slower, right? This could be easily installed, switched on when needed, and easily removed if so wished for. Of course it would register less driven distance also, which will result in lower odometer reading which is illegal for sure. And it might mess up the tranny calculations... Maybe I'll give it a try some day. It would be nice to go a little faster. It's sometimes hard to be beaten by a Diesel-Mercedes or Audi! Stefan Link to comment Share on other sites More sharing options...
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