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2001 Eldorado - Electrical Hiccups, possibly faulty ground. Theft System / Airbag / Traction Control lights.


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Hello, Hope everybody is doing well in these times! I've got a tricky electrical situation that I just can't get to the bottom of, and I've seen lots of unresolved threads with the same issue. I've noticed that after a car-wash, or long drive in moderate to heavy rain, I'll experience what seems to be the instrument cluster powering off, followed by the flashing orange 'PRNDL' indicators in between the speedo and tach, and multiple display warnings of "Theft System Problem", "Service Airbags", and the Traction Control / Airbag warning lights turning on. The climate control will sometimes blank out, other times it will default to full defrost on the hottest setting. Recently had a new battery and alternator, but this would occur prior to that as well. Battery connections are all clean and tight, AC-Delco OEM alternator. To make matters more interesting, when I check the codes there usually are none, but sometimes a whole bunch of "U100X" communications errors will be in the history for just about every module. After the car 'dries out' for a day or so, problem is gone, and she runs/drive beautifully.

I'm fairly convinced this is an issue of a faulty ground or crusty relay, but I can't figure out where to look. I've cleaned up every ground I can find under the dash, and back seats. I'm not sure where to start under the hood. Almost guessing this has something to do with the ignition switch relay (not sure where to find that...), as it feels like it's powering off while the car is running, causing the gauges to drop out, and the airbag/tcs/etc systems to 'reboot' when they were already running. Jiggling the key doesn't seem to have any effect. Sometimes giving the car a good 'rev' will trigger the fault, which makes me think the jump in voltage is breaking a weak ground somewhere.

I've read several threads of people changing out the ignition switch (key), bypassing the VATS, and swapping out the wiring harness up the steering column, with no positive results. I'm fairly convinced this is a relay or rotted-out ground box, based on the fact it happens when the car gets wet. Just not sure where to look. I do know I have a leaking sunroof, as back when this was my daily-driver car, I would have to be careful to ensure the car was parked 'nose down' on slope in the rain, otherwise the back seat area would get wet. I'm almost tempted to say the problem rests somewhere in that rear-shelf module area, but nothing looks obviously wrong, and the connections I can see appear clean and dry.

Thanks for any insights!

 

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Hello.

Welcome 

Few things to check here. 

First off Battery and connections. Actually remove the stud from the cable ends and closely inspect them.

The lugs are supposed to bite into the battery terminal when tightened. If they are flattened then I recommend replacing them.

2. Pull the electrical center cover off driver side strut tower. Closely inspect relays, wires, etc... there. (my bets are the issue is somewhere there)

3. Check the 3 relays at the bottom of the radiator support. They are low on the vehicle and if not sealed can cause issues. They are for the cooling fans.

Please post a few pics of what looks to be a beautiful Eldo

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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22 hours ago, BostonETC97 said:

Thanks for the reply! Battery connections look clean and tight, although I'd like to follow the negative lead and clean up where it attaches to the body and engine block. I haven't pulled the cover off the strut tower 'electrical center', and I think you're right that it's where the problem lies. Water can easily enter from the gap in the hood, and run straight down the fender, into that area. Next warm day I'll start going through that area. I do hear the fans running as they should, so I'm guessing the relays by the radiator are happy, but I'll definitely crawl under there and take a look.

Here's a link to a photo of my car! Bought it back around 2010, to replace a black 1997 ETC I had driven for 10 years or so. I'm not a huge fan of the carriage top, but removing it would be more effort than it's worth. Unfortunately, the car now sits in a garage, and gets driven a few thousand miles a year. Just broke 80k miles, and still drives great. I'm always impressed that she starts right up after sitting for months, and overall has been very reliable. Considering there really aren't any "large comfy luxo-coupe" options out there anymore, I guess I'll be keeping the Eldorado a bit longer!

https://drive.google.com/file/d/1_8xuAX6Z29jE9TMr6N9HBTIP5JNPtq6e/view?usp=sharing

 

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Hmm...20 year old car. 

I count 17 grounds in the service manual. They are all over the place. 

All the computers 'talk' to each other on a network. If one of the computers or the cluster goes bad it can corrupt and pull down the whole network. Hence your U1000 codes.  

 

As mentioned.....the fuse / relay center can also rot out and cause multiple problems. 

 

The rain is a clue....the leaking sunroof is a clue.

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Thanks Logan. I missed the moonroof leak part.

1 of 2 things there. Either the drains are plugged, or one of the hoses popped off the tray. 

You could take trimmer line and run it upwards through the lines to help clear debris.

When the lines get plugged it fills up the tray too much and causes it to leak.

I loved the carriage top on my 96 Deville. Had the Opera lights and all. But on a Eldo I am not so sure. Some could pull it off like yours does.

Absolutely love the body on yours. That spoiler really tops it off as well. I had a 96 Same color. 

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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After letting the car sit in the cool/dry garage for a a day, no error messages, and everything is happy once again. I took the cover off the electrical center by the front left strut tower, and tried to make ends of it. Everything had a layer of grit on it, but no obvious signs of corrosion or water damage. Pulled some fuses, the blades are a little oxidized, but no rust or green buildup anywhere to be seen. I'm tempted to start pulling all the connectors off the pcm, and all the modules I can access, give them a cleaning, and re-connect them. Another part of me fears I'll break a pin/module/connector in the process, and cause absolute chaos. If there's one thing I've learned about older cars, it's that a good-intention "$5 fix" almost always snowballs into a $1500 lesson about not kicking the hornet's nest.

I'll take a hard look at the sunroof. It's time I get that leak under control. Where do the drain hoses run to? I do notice that after a long drive in the rain, I get a constant dripping for two days behind the driver's side front wheel. It drips so much the puddle extends well past my parking space. Clearly something is blocked, and I'm guessing it's those lines.

Can't say I've warmed up to the carriage top too much. Creates wind noise at speed, and covers up one of the most beautiful design aspects of the Eldorado - the massive and gorgeous rear pillars. I do like the spoiler, however. I just wish whoever ordered this car back in 2001 either picked "frumpy" or "sporty", but instead checked off both boxes. Makes it unique, I guess! The most interesting part is that I have the original window sticker, with the "addendum" showing the car came with some type of two-tone gold and chrome wheels, and Vogue tires. Those must have been ditched sometime before I bought the car. Too bad... the wheels/tires are probably worth more the car!

 

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Your lucky if you can actually see the water getting in........many water leaks run down inside metal panels and under plastic trim panels etc. 

Anyway.....kind of a generic Cadillac sunroof drain(s) diagram. #14 (x2) and #18 (x2). See 'View A'

If they are connected ok up top.....they can be clogged or partially clogged or pinched and will only back up in moderate rain. 

sunroofdrain.jpg

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I do not recommend checking the connectors to the ECM just yet. To date I have never had a problem with one. 

Check the relays at that electrical center, check the plug that is wide. Located right in that electrical center. It should be easy to see.

30 pin possibly. Wide with 2 rows. I have run into many issues with that one. Unplug and very closely inspect the pins on the mating side and the wire side. I have seen them go bad on both sides. Not sure why they did not insulate that plug

plug Seville.jpg

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Thank you both for the FSM photos of the drain lines, and the picture of the connector! I'll take a look this afternoon and see what I can find. What's the best way to clean up the connectors and relays? I don't want to be too aggressive and start destroying pins. Electrical contact cleaner and a soft brush ok?

Thanks again!!

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Yes. You can actually see the corrosion on the pic I posted. One of the pins was actually corroded off on the wire side. Only thing holding it together was the insulation

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Bizarre update! I pulled the wide connector at the electrical center, and surprisingly, it was very clean. Shiny contacts, pins all in like-new condition, no signs of decay on the connector or wires. Haven't driven the car in a week or so now, so took it for a 30 minute drive. Halfway into it, flashing "PRNDL", "theft system problem", and the airbag and traction control lights were back on. A few moments later, HVAC is blowing full hot on defrost, and the radio/HVAC displays go dark. Tested the alternator output, still getting 13.6 or so volts, rises to 14ish with a rev. Engine still runs fine, but everything electronic is wonky. Fuel and temp gauges fall to zero, but will intermittently pop back to life.

Got home, and turned the car off. Now it won't restart. Tried unplugging the battery, cleaned the contacts, reconnected. No start, "Theft System Problem" warning, followed by airbag light. Eventually (here's an observation) the headlamps pop on while the car is left in the "run" position, and boom, it restarts. Still getting wild errors, but at least now I don't have to push it back into the parking spot.

I'm puzzled by this! Clearly somewhere a module, or connection, is dropping out. I did pull the codes below.

PCM: All History codes: U1040, U1056, U1096, U1152, U1300

IPC: All History codes: B2750, U1016, U1088, U1040, U1152

ACM, History codes too... U1096, U1064, U1016, U1153

SDM History: B1163, U1300, U1301, U1096, U1064, U1016, U1040, U1255

TCS History: U1300, C1298, U1056, U1016,

PZM: Again, all history codes... B0533, U1300, U1088,

IRC History: U1300, U1129, U1305

RFA: History - U1305

If anybody knows of a decent shop around the downtown Toronto area, or even in the suburbs outside, let me know! I'd be happy to leave the car for a while if someone wants to sort this out. I'm fairly hands-on with this car, but have an odd feeling I'm in over my head with this problem.

Thanks for the help!

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With a bit of google-sleuthing based on my codes, I did find the post below from another Cadi forum. I'll have to take a look tomorrow and see how my under-dash ground wire looks. Assuming it's going to be similar on my Eldo to a '98 Deville. Almost identical symptoms too!

 

1998 Deville VIN Y - VATS bypassed some time ago, Replaced alternator due to the "low voltage message" and codes. Around about the same time this started:

When the left turn signal is used or turning on the twilight sentinel the dash will go blank. When you turn off either of these the dash lighting comes back but it is "scrambled" The inst/avg will read "---", the "PRND123" will have little circles around them flashing, and if the car is off the security message "this car may not restart" is displayed. I have found the car will not start if you set the "TS" on and off or turn the left turn signal on while the car is not running. But if you wait for the delay timer to turn off the car will restart with no issues. I am driving this car everyday and have zero issues as long as I remember not to use the left turn signal. Also the "headlights suggested" message display even tho the headlamps are on. Could the alternator that failed have caused this? (I have a video of what it is doing just don't know how to share it)

Here are the codes stored

P1604 Loss Of IPC Serial Data Conditions - Current
P1626 Pass Key® II Fuel Enable Circuit Conditions - History
B1552 Keep Alive Memory (KAM) Error - Current
B1910 Generator L-Terminal Open Circuit - History
B1911 Generator L-Terminal Problem - History
B1981 Battery Voltage Low - History
B1983 Device Power Circuit Low - Current
B2750 PASSKey Data Communication Failure - Current
U1016 Loss of Communications with PCM - Current
U1064 Loss of Communications with DIM - Current
U1088 Loss of Communications with SDM - Current
U1040 Loss of Class 2 Communications with ABS - Current
U1152 Loss of ACM Serial Data Communication - Current


Could really use some advice on where I should be hunting. Was thinking a ground issue but if that were the case wouldn't it be a little more erratic and not so consistent? Leaning towards a PCM or the BCM (found out that there were 15 updates on the Body Control Module from the number on mine). Thanks in advacne
 
 
 
 

 

**SOLVED**Re: Chasing Gremlins...Need help

About three weeks ago the car started to loose all power and shut off while driving or just would not start at all. So I had the car towed to a shop that deals with electrical issues and put the car in their hands. Today I got the call, the "Gremlin" has been found. Turns out that the G203 ground wire under the drivers side kick panel was severed. They said it looked like a clean break, repaired the wire which solved all my issues. No more codes and the voltage is now normal. The shop that I finally took it too did a bang up job in not giving up and tracking the problem down.
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It never hurts to inspect, clean, and resecure grounds.

That one should be easily found. I believe it was just between the dash and the kick panel on the far left.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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No luck with either of the grounds in the car, under the dash. Both were clean and tight. Took them off to clean and re-tighten, just to be sure. I'm now leaning towards the possibility of a faulty PZM. The only other observations I've made is that the car will cold start perfectly, but the moment it revs beyond 2-3k, the theft warnings start popping up, and the fuel/temp drops out, along with the radio/HVAC. If you put the car in reverse, everything pops back to life. Other observation is that the the LEDS on the shifter go dead, and the foglights/highbeams are inoperable when things are 'wonky'.

I was hoping for a corroded ground *somewhere*, but it seems everywhere I look the wiring and grounds are clean and tight. Time to start digging into the rear module area. What a PITA, but I'm not giving up yet!

 

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Sort of a sad update. The car wouldn't restart after a short drive to do some errands today. Opened the hood, found the left radiator fan motor has somehow come in contact with the flexible exhaust tubing for the AIR system (I think that's what's up front there...), and was causing some major arcing, snapping, sparking, and overall just shorting out to the point the exhaust tube was charred and blackened where it was in contact with the fan. Once they were no long shorting, the car wouldn't start, and just kept flashing all the dash warnings, "theft system problem" etc. Finally got it towed after waiting for hours, and it's off to the Cadillac dealer. I'm guessing the high amperage fan was sending voltage all over, and it cooked a module or two. I'll wait to hear the estimate, but I'm guessing the cost to repair is going to outweigh the value of the car. Sadly, I don't know any mechanics locally, and the few I called wanted NOTHING to do with an older Cadillac. I usually dread sending anything off warranty to the dealer, but had no choice. As frustrating as this experience has been, it's really been a great car for the over 10 years I've owned it, and this is truly the first 'real' time it has left me stranded. Here's hoping I get a call that they found a cooked relay, and she's back on the road again!

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Hmm.

You are on to something.

When you rev the engine it will rock slightly, when you shift into gear it will rock slightly.

I bet high revs and reverse shifting rocked the engine forward enough to touch the fan. If the AC was on at the same time I am thinking that is the fan that would be running.

I wonder how it came into contact. I have yet to ever have that happen. I know they are close but it sounds like you either have a torque strut(s) issue or the fan was not mounted properly.

I hope for you that they are honest and will resolve the issue. 

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Just FYI.....Most GM cars will not rev much above 3000 rpm in park or netural. The car will kind of go into self protect mode. 

To me....it sounds like somethings wrong on the network. Intermitant network problems can be very difficult to sort out.

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Final update! The dealer turned out to be the best decision I made. The service manager and a couple of his techs were incredibly happy to see this car, and were around 'back in the day' when these were a bit more common. I told them about the shorted left cooling fan motor, and after a couple hours of cleaning contacts, determining that the harnesses were OK, they discovered that the fan itself had a severe internal short, and whenever the PCM would call on the fan to activate, it would short out and throw voltage around, causing my havoc. Now makes sense why the car would cold-start perfectly fine, but once warmed up, the fan would activate, and cause trouble. Also explains the intermittent nature of the problem. Once they had the fan disconnected, the PCM, Theft System, ABS, Airbag, PZM, etc etc problems were gone. We got lucky no modules were cooked, and the wiring harness survived. New fan is on order, and they want to spend a little time cleaning up the grounds by the engine and ABS module.

I really thought this was the end of the road for this car, but I'm thrilled I get to keep her a little while longer! Only 80k miles on it, so I'll keep driving!

Thank you all for the help - great forum here!

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Great. 

Always be optimistic. Honestly the modules most rarely fail. I have never had one yet. It is almost always caused by a wire or component.

This does not apply to all vehicles but most of them

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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