bc6t Posted January 17, 2006 Report Share Posted January 17, 2006 The lights on my 98 STS located on the trunk lid stopped working. First off I am not sure which lights should be on or off. For sure my backup "white" lights are no longer coming on in reverse and the 2 lights "red lens" beneath each "white lens" backup light do not come on at all except when I use my key fob they blink (in an alternating fashion on each side) very dimmly to show the car is unlocking. This means power is actually getting to these lights. Question 1: Are the 2 "red lens" lights on each side of the trunk lid suppose to be both driving and brake lights under normal conditions, i.e. when are they suppose to be on? Question 2: The reverse light bulbs are in good shape so I think it's maybe a bad wire, bas relay or bad reverse transmission switch - but how is it possible for the 2 "red lens" (on each side of the trunk lid - 4 in total) lights to stop working at the very same time. Is it possible that if one of those 4 bulbs went out that it would trigger all 4 lights and the 2 backup lights to lose ground? Is it a serial circuit? I haven't checked the 4 "red Lens" bulbs yet. The bulb removal process is quite time consuming.....saving it for the weekend.... Any thoughts or experiences would be much appreciated...Thanks in advance. Oh - forgot to mention that the center brake light strip on the trunk lid is working perfectly. Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
OynxSTS Posted January 17, 2006 Report Share Posted January 17, 2006 I'll check the wiring diagrams tonight when I get home... Did you find your service manuals? If you can't fix this I'd trade her in on one of those STS-V jobs... Tomba, that car is you! Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
tommysls Posted January 18, 2006 Report Share Posted January 18, 2006 The lights on my 98 STS located on the trunk lid stopped working. First off I am not sure which lights should be on or off. For sure my backup "white" lights are no longer coming on in reverse and the 2 lights "red lens" beneath each "white lens" backup light do not come on at all except when I use my key fob they blink (in an alternating fashion on each side) very dimmly to show the car is unlocking. This means power is actually getting to these lights. Question 1: Are the 2 "red lens" lights on each side of the trunk lid suppose to be both driving and brake lights under normal conditions, i.e. when are they suppose to be on? Question 2: The reverse light bulbs are in good shape so I think it's maybe a bad wire, bas relay or bad reverse transmission switch - but how is it possible for the 2 "red lens" (on each side of the trunk lid - 4 in total) lights to stop working at the very same time. Is it possible that if one of those 4 bulbs went out that it would trigger all 4 lights and the 2 backup lights to lose ground? Is it a serial circuit? I haven't checked the 4 "red Lens" bulbs yet. The bulb removal process is quite time consuming.....saving it for the weekend.... Any thoughts or experiences would be much appreciated...Thanks in advance. Oh - forgot to mention that the center brake light strip on the trunk lid is working perfectly. Yesterday I had to change my pass side brake light. When I removed the lamp assembly from the rear panel I noticed that it was full of water and that the bulb had burst. Replaced the bulb and it worked fine. All other rear lamps worked fine. So I doubt it's in series. The light assembly removes easily on the 98 - just unscrew it from inside the trunk and pop it out - only took a few minutes. Now I have to fix the water leak. Looks like the lens is seperating on the side. Good luck. Tommysls Link to comment Share on other sites More sharing options...
OynxSTS Posted January 18, 2006 Report Share Posted January 18, 2006 OK TOMBA As per the book and I'm paraphrasing here... 1) You've checked the bulbs... right?. 2) Take out the back seat and check the NSBU 10A fuse If its blown you have a short somewhere that you need to fix... 3) Turn the ignition on and put the car in "R" 4) Back probe with your digital volt meter Cavity B7 (Dark Green) in the rear fuse block to ground If you don't get 0.5 Volts the RIM (Rear integration module) is shot... Looks like this is expensive as it controls all kinds of stuff not just the back up lights... 5) Back probe with your digital volt meter Cavity C8 (Light Green) in the rear fuse block to ground You are looking for 10 to 15 volts... If you don't get 10-15 volts the reverse relay is shot 6) If you do get 10-15 volts you have an open (broken wire) or burnt out bulbs... you did check the bulbs right! Oh and by the way... when I unlock my car with the remote the back up lights are BRIGHT... and all of the red ones on the back of the car light up too... I'm betting (hopping for you actually) on a bad relay... PS the "red" tail lights are on a totally separate circuit, the same one as the center and stop lights and look like they have nothing to do with the RIM, but they do go through the rear fuse block (Cavity C5 Orange). I would bet they are burnt out... I've replace two of mine on my '02 already... Did This help? Good Luck... Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
bc6t Posted January 18, 2006 Author Report Share Posted January 18, 2006 OK TOMBA As per the book and I'm paraphrasing here... 1) You've checked the bulbs... right?. 2) Take out the back seat and check the NSBU 10A fuse If its blown you have a short somewhere that you need to fix... 3) Turn the ignition on and put the car in "R" 4) Back probe with your digital volt meter Cavity B7 (Dark Green) in the rear fuse block to ground If you don't get 0.5 Volts the RIM (Rear integration module) is shot... Looks like this is expensive as it controls all kinds of stuff not just the back up lights... 5) Back probe with your digital volt meter Cavity C8 (Light Green) in the rear fuse block to ground You are looking for 10 to 15 volts... If you don't get 10-15 volts the reverse relay is shot 6) If you do get 10-15 volts you have an open (broken wire) or burnt out bulbs... you did check the bulbs right! Oh and by the way... when I unlock my car with the remote the back up lights are BRIGHT... and all of the red ones on the back of the car light up too... I'm betting (hopping for you actually) on a bad relay... PS the "red" tail lights are on a totally separate circuit, the same one as the center and stop lights and look like they have nothing to do with the RIM, but they do go through the rear fuse block (Cavity C5 Orange). I would bet they are burnt out... I've replace two of mine on my '02 already... Did This help? Good Luck... Thanks for the info... 1) All bulbs visually inspected and metered to be good. 2) NSBU 10A fuse is ok. 3) - 6) I don't know what Cavity B7 or C8 is or where to find them. The fuse box under the rear seat does not have any markings whatsoever. Without a picture its impossible to find the right cavity. I did put the voltmeter on the connector that goes to the trunk lid lights and got no readings, also switched out the reverse relay with no success. Then battery died and am in the process of charging it back up - cause that's how god works. Try to fix one thing and another goes.... Pulled some codes and will need to get my hands on a service manual to decode.... AMP U3132, U1128, U1162 DDM U1163 IPC B1652 TTM B1983 I don't have a good feeling about this problem now. I am thinking of just hardwiring a manual reverse switch and to hell with the dirvin/brake lights on the trunk lid. Any ideas - have I missed something obvious.... Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
bc6t Posted January 18, 2006 Author Report Share Posted January 18, 2006 I quickly searched the net and the codes (one of them is wrong) seem to be realted to my battery failure - nothing about the Rear itegration Module. I think it's possibly a gremlin. Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
OynxSTS Posted January 19, 2006 Report Share Posted January 19, 2006 This is going to be a challenge... I have scans of the '98 manual that show where you need to stick your meter. On the back side of the fuse block there are three connectors C1, C2 & C3 All of the power and relays of interest come from the C1 Block I have attached an image of it... The holes are labeled "battle-ship) style from the bottom corner up A1 Orange Positive Battery A2 Not Used A3 Brn/White Park lamp feed A4-A7 Yellow Fuse Lamps A8-A9 Not Used A10 Brown Ignition Positive Voltage A11 Orange " " " A12-B1 Not Used B2 Yellow Ignition Positive Voltage B3 Brn/White Park Lamp Feed Right B4 Purple Park Lamp Feed Left B5 Pink/Black Park Relay output B6 Lt Grn Neutral Safety Switch output (park) B7 Dk Grn Reverse Relay Coil B8 Lt Grn Back up lamp feed B9 Not used B10 Brown Ignition Positive Voltage B11-C1 Not used C2 Yellow Ignition Positive Voltage C3-C4 Not used C5 Orange Battery positive voltage C8 Lt Grn Back up Lamp Feed C9 Oragnge Battery positive voltage C10-C12 Brn Ignition Positive Voltage D1 Not used D2 Black GROUND D3 Not used D4 Drk Grn Control Power output D5-D8 Not used D9 Pink Ignition Positive Voltage D10 Dr Grn Cigar Relay Control D11 Brown Ignition Positive Voltage D12 Not used E1 Yellow Ignition Positive Voltage E2 Grey Fuel Pump E3 Not used E4 Purple Park Lamp Feed Left E5-E8 Not used E9&E10 Orange Battery Postive Voltage E11 Brown Ignition Positive Voltage E12 Orange Ignition Positive Voltage F1 Grn/Wht Fuel Pump relay F2 Grey Fuel Pump F3 White Park Lamp Relay F4 Not used F5 Orange Battery Positve Voltage F6-F10 Not used F11 Brown Ignition Positive Voltage F12 Orange Battery Postive Voltage Connector C2 has no exterior lights on it controls trunk release, fuel door release, courtesy lamps, and the parking brake Connector C3 supports the rear A/C blower, CVRSS, defogger, level control and the RAP (whatever that is..) PS You owe me a beer.. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
bc6t Posted January 20, 2006 Author Report Share Posted January 20, 2006 Oh...I feel an ulcer coming on... I know it's not the bulbs or the physical wires and no DTC codes. It must be a fuse or relay - but which one? What do the reverse lights, licence plate lights and trunk lid driving/brake lights share in common? Some module? Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
OynxSTS Posted January 20, 2006 Report Share Posted January 20, 2006 Holly Crap Tom! They are all out?! The only thing these circuits seem to have in common is "D2" GROUND! Tommorow at work I'll find the routing from D2 To ground... You might want to test the resistance between D2 and a metal part under the seat.. If its not zero you've got a loose ground somewhere I feel your pain. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
bc6t Posted January 21, 2006 Author Report Share Posted January 21, 2006 For those interested - Problem Solved. Cost me $0. Thanks to the expertise of OnyxSTS, I was able to narrow down the common components for these lights and we figured it was a bad ground somewhere. True enough, the repetitive openning and closing of the trunk eventually took its toll on the black ground wire and snapped it. One wire connector and electical tape solved the problem. Over time, given the design of the wire feeds to the trunklid lights, I can easily see this happenning to others as well - so if any of your lights on the trunklid fail - confirm the ground connection first and then work your way to the harder stuff. Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 21, 2006 Report Share Posted January 21, 2006 Nice work guys, this is one of those things that GM would love to know about..... Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
OynxSTS Posted January 22, 2006 Report Share Posted January 22, 2006 Glad I could help! The auto dim rear-view mirror being "out" was the clincher. They are all on the same circuit... Did the black wire fix this too? Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
bc6t Posted January 22, 2006 Author Report Share Posted January 22, 2006 Yes, my autodim mirrors are working again too. Thank god someone can actually interpret the wiring diagrams in the manuals. I am starting to think that GM just keeps designing new stuff based on adding to old designs. If I were to design the electronic ona new car I would definitely loop back each electical item on its own loop/ring, otherwise it makes it difficult to diagnose problems.... Props to OnyxSTS (aka Greg). Tom R. 1998 Cadillac STS with 102K Miles Link to comment Share on other sites More sharing options...
Seattle1Seville Posted May 21, 2006 Report Share Posted May 21, 2006 Hello Folks. I too would like to thank OynxSTS and all the participants here. I had the very symptoms listed in this thread ( with my 1998 Seville SLS ), particularly both backup lights out and a few other electrical abnormalities. After testing and passing the fuse ( NSBU 10A ) and the Relay, I was stumped. Then I did a search of the internet and came upon this thread. Sure enough, I had a broken ground wire, and at the exact location mentioned, the trunk lid hinge. I soldered and patched it and everything works perfectly, no more anomalies, bright and shinny backup lights when appropriate. Also, my charge voltage has quite fluxuating and remains a steady 14volts. One thing though, the break in the ground wire was a clean cut, no abrasion, flexing or stretching. I'm wondering if, perhaps, this is a dirty trick by some unethical mechanic. It sure is hard for an ordinary owner to discover. I have experience working on vehicles, even pulled a few engines, I'm an amateur but have been able to perform all but the most involved repairs on all my vehicles. Still, without the help of OynxSTS, I would probably never have solved this one myself. It sure would be easy to pad a repair bill with something that can easily be disguised as myriad costly electronic problems. Link to comment Share on other sites More sharing options...
Ranger Posted May 21, 2006 Report Share Posted May 21, 2006 Anything is possible. Did your problem begin right after you had some work done? Link to comment Share on other sites More sharing options...
Seattle1Seville Posted May 21, 2006 Report Share Posted May 21, 2006 Anything is possible. Did your problem begin right after you had some work done? Well, that's where it gets funny, Larry. I just purchased the car about 2 days ago. I've purchased so many used cars and have seen so many frauds and cover-ups that I've come to believe that nine times out of ten, when someone is selling a used car, they're trying to dump something with some serious problems, serious enough to cause them to sell it when they normally would not. If you look hard enough you will find the one in ten which is someone who buys new every 4 years and knows they'll get more for selling privately than trade in, which is what I look for. There are other reasons as well. I always say the "Owner diagnostic" is more important than the "Auto Diagnostic." Anyway, the Caddy was selling really low, the owner was claiming it was perfect ( 79,000 miles and in great apparent shape ), so I assumed it had some serious problems but since it was selling cheap, I thought salvaging a few parts alone would be worth the price, as I had planned on getting the same model and year anyway. For a variety of logistical reasons, I didn't do a diagnostic or even a detailed point check on the thing. Turns out, as I expected, that it had these electrical problems ( mentioned in post above ) So, as I'm making a tally of all the parts I knew were good, planning to strip the thing, I wasn't sure if I could trust the rear light assembly ( $600 new, but I noticed on this site you can get them rebuilt with led's for $149! ) That's when I did some research which led me to this site. Now it's been repaired for days, and $0 ( that's zero dollars ) and it runs and rides better, frankly, than any car I have ever owned. I love this car. So to make a long story short ( whoops, too late for that ), I think this guy's mechanic might, I say might have scammed him, and he just wanted to get rid of the thing, albeit not very honorably. I guess I don't really much care, either way, I'm going for a ride now. Link to comment Share on other sites More sharing options...
KHE Posted May 21, 2006 Report Share Posted May 21, 2006 Glad to hear you found a good car - the wires will break over time depending on how frequently the trunk is opened/closed. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
OynxSTS Posted May 22, 2006 Report Share Posted May 22, 2006 Hello Folks. I too would like to thank OynxSTS and all the participants here. I had the very symptoms listed in this thread ( with my 1998 Seville SLS ), particularly both backup lights out and a few other electrical abnormalities. After testing and passing the fuse ( NSBU 10A ) and the Relay, I was stumped. Then I did a search of the internet and came upon this thread. Sure enough, I had a broken ground wire, and at the exact location mentioned, the trunk lid hinge. Glad I could help... Tomba (bc6t) and I struggled on this one for a couple of days. The DVD manual I bought off of ebay was the tool to help figure this out... Once you know what runs on what circuit it become quite clear... and wire having the appearance of being cut it normal that's what they look like some time. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
02Deville Posted February 8, 2009 Report Share Posted February 8, 2009 For those interested - Problem Solved. Cost me $0. Thanks to the expertise of OnyxSTS, I was able to narrow down the common components for these lights and we figured it was a bad ground somewhere. True enough, the repetitive openning and closing of the trunk eventually took its toll on the black ground wire and snapped it. One wire connector and electical tape solved the problem. Over time, given the design of the wire feeds to the trunklid lights, I can easily see this happenning to others as well - so if any of your lights on the trunklid fail - confirm the ground connection first and then work your way to the harder stuff. THANK YOU,THANK YOU !!!!! i spent numberous amount of times trying to find the problems on why my back up lights doesnt work on my 02 Deville for a year .. (Didnt want to take it to a repair shop) I open the trunk and look on the left side by the hinges and saw the wires cut.. i taped it together and finally it works Fixed it today on 2-7-09 Thanks again...This place is very helpful! Link to comment Share on other sites More sharing options...
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