Digital Dash Repair - Ideas how to resolve speedometer and cluster problems
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Cadillac Tech Tips - How to fix it Discussion, Digital Dash Repair - Ideas how to resolve speedometer and cluster problems in Item Specific Cadillac Discussion; Digital Dash Repair Tips: Digital clusters can be problematic in Cadillacs ...and other cars. It seems there is a deficiency ...
  1. #1
    Mark G is offline Cadillac Owners Member
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    Exclamation Digital Dash Repair - Ideas how to resolve speedometer and cluster problems

    Digital Dash Repair Tips:

    Digital clusters can be problematic in Cadillacs ...and other cars. It seems there is a deficiency of good troubleshooting info, or it is scattered in several posts. Hopefully we can get a thread going that will be useful for those who want to "hunt" down and resolve problems w/o paying a king's ransom. I invite others that have resolved dash problems to share their troubleshooting methods. If enough information is added, perhaps this can be a "sticky" thread to help others.

    Problem: For me, it all started with an annoying intermittent cluster problem in my 92 Seville that became more and more pervasive. Here were the symptoms: After about a 1/2 hour or so of operation, the cluster would go completely dead, all needles flatline and radio light blank. The fuel data and HVAC lights would flicker and finally go blank. As a result, the HVAC system would go into a default defrost mode and 75 degrees heat (annoying in the summer and winter).

    Finally, I got serious about fixing the problem. Since it was an intermittant problem I figured it would be relatively easy to spot and resolve. The following article is the steps I took to do that. I have some very basic electronics repair experience which helped, but anybody with decent mechanical skills should be able to apply the same strategy. I may might do a more detailed write-up on on my website (www.RepairNation.com) in the future with some pictures.

    There a number of things that can cause intermittent problems like this: The VERY first thing to check is the ground on the starter and body. This was such a problem in the early 90's that Cadillac came out with a special ground bracket to retrofit cars with. My neighbor works at a Cadillac dealer and he says that a bad ground was the number one problem that caused digital cluster to flicker. Don't do any repairs w/o ensuring you have proper grounding.

    It's important to know that the following modules all communicate on a Serial Data Line:
    PCM - Powertrain Control Module (the ECM)
    ACP - Air Conditioning Programmer (for the HVAC))
    DERM - Diagnostic Energy Reserve Module (GMs fancy term for the Air Bag system)
    EBCM - Electronic Brake Control Module
    IPC - Instrument Panel Cluster

    Information from these separate computers share information on a **serial** data link to the cluster. It's a loop so if only one break in the circuit occurs, it will not necessarily cause a loss of communication (com can go the other direction in the loop). But issues with one module can have rammafications with the performance of the dash/cluster and that makes it particularly challenging to troubleshoot the system. To pay a Cadillac dealer to track down dash problems will most likely cost a prince's ransom. Fortunately, there are onboard diagnostics you can access that may aid in pinpointing some problems. To access the diagnostic mode turn the ignition to "on" and hold the "Off" and "Warm" buttons down simultaneously for a few seconds. Initially, ALL the lights in the cluster will illuminate (test mode) then it will go into the diagnostics mode. Record the trouble codes if any. Maybe someone would like to post the codes and what they mean. Pressing "auto" will take you out of the trouble-code display mode.

    Basically on mine, the trouble codes didn't do me any good. My neighbor who has worked as a mechanic at Cadillac for 15 years says they don't often point ya to the problem, in his experience. To pinpoint the problem I resorted to an old trick electronic repair technicians use that involves careful use of a hair dryer and freeze spray. This strategy works on the principal that the majority of electronics failures are due to poor solder joints (cold joints), and leaky or dried-up electrolytic capacitors. This is an ideal trick for uncovering intermittant failures.

    Getting Started:
    I started out with my PCM. I removed all the shielding and heated the circuit board up with a hair dryer while the car was running. I was not able to make the dash flicker or go blank this way. When the dash did go blank after some time (like usual), I used freeze spray (abailable at www.partsexpress.com) to chill sections of the board and observing the effects on the dash. Chilling board or components on the board had no apparent bearing on the dash problem. Of course I wiggled connections and all that too, to no avail. I put it back together and moved on.

    Next I inspected the connections for the aforementioned computer modules which, in a 92 Seville, are located in the trunk behind the back seat. Nothing I did back there seemed to have any relavence on the blanked-out dash (or made it flicker when it was actually working). I moved to the last thing, the IPC - Cluster. I removed the A-pillar covers, then the dash pad to reveal the cluster. Then I drove the vehilce until the IPC would flicker or blank-out as usual. When the dash would go blank I shot freeze spray through a hole in one end, watched observed the effects, then did the same to the other side. I was able to consistantly make the dash lights and gauges work properly with this method. At this point, I knew the problem lie in the cluster electronics. Time to dig a little deeper.

    Working on the cluster:
    I pulled the IPC from the car [see notes below] and very carefully removed all circuit boards from the cluster housing, and taped them to a 3' wooden board with masking tape (to hold the boards from sliding around). I transferred the whole assembly back to the vehicle, plugged it into the harnass and started the car. Now that I had all boards laying out in the open in front of me I could do some real diagnosing. I went around with the hair dryer, one section at a time keeping my eye on the dash for any flickering. I worked section by section. Eventually I heated up an area that would consistantly cause the dash to blank-out. Shooting freeze spray in that area would make it operate properly again. I was expecting the problem to be a bad capacitor. But there were no capacitors in this area.

    Investigating further, I tapped around the region with my finger [be sure to discharge static from your body beforehand, or wear a wrist strap]. Everytime I tapped one corner of one of a particular processor-style chip the dash would cut out (go blank). I barely had to touch the corner. It was unmistakably consistant. I narrowed it down further to one pin on that microchip. Touch that pin [with a plastic instrument] it would go blank or flicker.

    Making the repair:
    I moved the whole dash assembly taped onto the 3' board into the shop and prepared to resolder that pin. Before soldering, I carefully chipped the clear circuit board protective spray coating (prevent's condensation problems) away from that portion of the chip. I carefully resoldered not applying too much heat (which could damage the microchip) and connected the dash to the car again. I was not able to make it "blank out" again. I heated the all circuit boards again with the hair dryer and was not able to get the dash to go out. Interestingly, the chip I resoldered resides next to the power regulator heat-sink (behind the HVAC Controls) when installed in the cluster housing. The heat produced by the regulator would cause a minor amount of expansion which would move the poorly soldered joint enough to break the power connection and cause the dash to blank-out.

    The repair has been a success so far. So, guys, there you have it - an example of how a specific oft-used electronic trouble-shooting technique was used to isolate and resolve a pesky digital cluster problem. It only took me about 15 minutes to locate the problem once I got the dash dissassembled.


    Other things to look at:
    There are a bunch of electrolytic capacitors and what looks like a switching or regulating transistor on the power regulating portion of the cluster (behind the A/C controls). I can see how these could be a source of cluster problems that one would want to investigate in the course of a digital dash diagnosis. Capacitors often leak and/or dry up over time. These are high quality capacitors but 10 years is a long time for these and cars get hot in the summer. Look for leaky or bulging (tops) features. They could easily be unsoldered and replaced if found to be faulty (capacitors are marked for size and capacity). Newark is a good place to buy replacements electronic parts.

    Hope this helps. Please share your tips and experiences.

    Mark G

    **IMPORTANT**----------------------------------------------------------
    1) Before working on your dash, remove your air bag (SIR) fuse and unplug the yellow connector below your steering column.

    2) Always be SURE to discharge static from your body before messing with any electronics or your car's Air Bag, SIR system. Wear a wrist strap or just tie some wire to your arm and ground it at the other end. You can never be too careful.

    3) Remove the IPC fuses in the trunk before removing your dash. Reinstall after hooking your dash back up.

    4) This is an example of a repair I made. The techniques used may not necessarily resolve your problems. Any repair attempts are made at your own risk :disappoin

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  3. #2
    momuzykent is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    im new to the board and have a 1992 seville that is doing the samething. trying to do everything before resorting to the dealer. where can i purchase the special ground bracket to retrofit cars that was metioned previously in this thread.


    thank youi!

  4. #3
    Mark G is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    You can get it from Cadillac. It's a little "L-bracket" with a bolt. I think I paid something like $13. It's an overpriced kit for what you get. You can go to NAPA and get a woven metal ground strap for a couple bucks and a internal toothed washer or two and do the same thing. It should go between the starter and the engine if I remember right. You just want to make sure there's a good connection at the starter. Also take a look to make sure the body is grounded properly. Your car may already have the bracket. I know mine did.

    Your cluster may have a similar probem mine had. Is yours time related?

    Mark G

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    Mark G is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    Here is a link to a picture of the dash repair described above.

    Dash Repair Picture

    You can see I carefully removed the circuit boards and unfolded and taped them onto a piece of wood about a yard (meter) long. Then I put it in the car so I could diagnose it. I pulled the Air bag fuse and unplugged the airbag connector below the steering column. After I connected the dash cables, I reinstalled the DASH fuses and started the car. I was able to work on the dash this way.

    Note: You can see I removed the needles and face plate to do a thorough inspection. If I were doing it again I would NOT remove this portion unless all other investigation fails. I had to play around with adjusting the needles.

  6. #5
    momuzykent is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    Yes mine is time related. it pretty much does the samethings you stated. when i start the car its fine. after about 15 to 20 minutes, it start to blink out, readings have "----" & my defrost defaults on to 75 which is hot in the summer & not hot enuough in the winter. thanks for the pic. im not an electronic genuis but can good at working on stereos, navigation systems, etc so do you think this is something the average person can do. if you are stating the L-bracket is more than likely already on the car, then i will more
    than likely have to take the dash apart which i dont want to do, but i will do it versus paying the dealer 300.00+ (the last resort). thanks for the info and any additional info you could give would be greatly appreciated.

    thanks,

    chris

  7. #6
    Mark G is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    Hard to say what the problem is, or if you can handle the repair. I would give it a try. On mine, when I touched the chip it would "flip-out". It was pretty obvious that was the problem. Yours could be the same or something entirely different. To me it seemed like it was pretty straight forward. Just remember to unhook your airbag, and also pull the dash fuses before removing the dash, and replace when you hook it back up. If you need to replace your dash, might consider: http://www.mrwhizard.com/

    Mark G

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    cadilux is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    after reading ur thread i trouble shoot mine. i have a 92 el dorado same problem w cluster fuel/climate ecm?code on display couldnt get heat or coolant temp check engine on.well after reading ur thread i got brave and i to took cluster apart and trouble shoot it after i heated it w/hair dryer it came on i could operate heat and all functions its been on for 2 days didnt finish fixin because i had 2 use the car but will try again today any ways for any body tryng i used the hair dryer directly behind the fuel data.that did it it came right on but i did make 1 mistake i used a voltage w/a little light bulb checker to chek climate conector for ground because i had juice i taught i might have been loosing ground. found the ground,but in the process did some thing now its on but the dic shows two rows of dots 1 on top 1 on bottom still work thoug and it added a 1on the otside temp now it read 129f but atleast i have heat would of helped in the ice storm we just had wasnt hard 2 trouble shoot thanx when i find my problem i will post it

  9. #8
    georgekelp's Avatar
    georgekelp is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    Ok i have the same problem, ill try that!

  10. #9
    Mark G is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    For what it's worth, I checked with our local Cadillac dealer and they charge $314 to send the dash in and get it repaired REGARDLESS of what repairs it needs (new boards, servos, etc). For those that can't resolve the issues or do not want to attempt surgery, this might be a good option. Personally, I didn't think that repair price was too bad all things considered. I talked to some of the dash repair places I found online, and these outfits typically look at your dash and call and give you a quote. The prices I was quoted (for hypothetical issues) was near the $300 mark, and some guys didn't have the capability to check/reprogram the EPROM and some other more detailed issues. I'm sure they offer good services and maybe for significantly less in some cases (depending on the dash problem), but another option is to let the dealer handle the repair.

    Bear in mind that the $314 is sending the cluster out through the parts department -- which means you would have to take it out.

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    Mark G is offline Cadillac Owners Member
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    1000 Mile Update!!

    1000 Mile Review:
    Well folks, it's been over 1000 miles since the dash repair, and since I originated this thread. I thought I would post the results up to this point for others to read. Basically the repair has been a success. Where the cluster would consistantly flicker and flash and eventually go blank, it has been working like a champ. It has not blinked, flashed or burped once. So, the repair has resolved the flashing dash issue. It's been a joy to drive the car with a good stable cluster (and having a heating system that works!).


    Remaining Issue:
    One issue I was not able to resolve during the repair is the mileage problem. I lost the mileage reading. At some point this fall (a couple months prior to my attempting to repair the cluster), the word "Error" replaced the miles. My sense is that the data on the EPROM has become corrupt, probably as a result of the repeated wild flickering and flashing it would go through on a daily basis. My initial thought was perhaps I had driven too many miles with the dash not working properly, and through a preprogrammed comparison algorithm between the cluster EPROM and the PCM it defaulted to "Error". Several luxury models including BMWs and Mercedes reportedly do perform a similar comparison to thwart people from lowering miles with a programming tool (available on the internet). Everything I have been able to gather on the subject indicates that the miles are stored ONLY in the cluster on this 1992 Seville and not compared to the PCM. I don't know this as fact, but the Cluster repair technicians I have spoken to have not seen this issue, and my neighbor works at the Cadillcac dealer and is very familiar with digital dash issues and also claims this to be the case. That being said, it would appear that my EPROM has been corrupt or some other issue remains. It's worth noting, the trip odometer functions properly.

    To dig into it a little further, I removed the cluster again and poked around the EPROM region to see if there was another connectivity issue. I was not able to get the miles to display and I could not see any other defects with the circuit boards. The dealer cannot reset the miles with their Tech II scan tool. The only way to get the miles back is to send it into the Cadillac dealer. A couple of the dash repair outfits I located on the internet and spoke to would not reset, or did not have the capability, to reset the mileage. So it appears I will have to send the cluster in to Cadillac if I want to get the mileage to reappear. The dash functions properly in every other way, so I have to decide if getting the odometer back is worth $314 to me (at this point I think it is just because it's such a nice car).

    I do know a computer programmer that I used to work with who has access to an EPROM programmer and is probably smart enough to figure out how to reset/restore the miles or the file (if there's anything to pull from the EPROM) ...and if I wanted to go through the trouble of desoldering the chip. But at that point, given the time committment and low probability of a successful outcome, it's too "iffy" to mess with -- although it does sound intriguing, doesn't it?

    Conclusion:
    It's good to have the dash back working properly, especially the heat in this cold winter. It would be nice to have the miles back, even though it is approxomately 128,000. I will probably remove the cluster at some point this spring and take it to Cadillac and fork over the $314 .

    Your comments/suggestions welcome.

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    John Becker is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    Friend Mark....Just found your repair tip...OUTSTANDING. Any suggestions for me would be appreciated. I have an Eldo 87 and an Eldo ETC 97. On both cars, the intensity of the Dash info, and speedometer back light, is washed out and dim in the daytime. The headlight switch does not control brightness in daytime, At night, everything works great and intenssity of displays can be regulated and adjusted. by the dimmercontrols. There is nothing that has not been replaced, and the dash unit has been rebuilt. Any ideas please...Many thanks, John Becker

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    torqmonster is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    I have a ī93 Eldorado TC Northstar. Since I own the car the SES light is on. Reading out the codes brought up "fuel system rich". Everything I tried didnīt cure the problem, including new spark plugs, new Oē sensors, ignition wires. The engine also never performed as well as it should and needs to much fuel. There appeared also some other trouble codes, which I could erase. Some came again, some not. some weeks ago the airbag warning light came on, first flickering, then constantly. I can not switch between the different functions of the driver information system since then, an additional airbag waring is always in the foreground. Now the needle of the speedometer sometimes fall down to zero while driving, usually at lower speeds. In the same moment the transmission shifts down. To me it looks like a bad connector, but may be itīs also the above mentioned ground problem. Any ideas?

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    Mark G is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    I was going to say that this would be a good issue to let a dealer handle, but then I noticed you were in Germany. Here are a couple ideas:

    1) If you don't have a Genuine GM service manual for this car, go on Ebay and get one. It's a very worthwhile investment because there are many electrical troubleshooting "trees" to guide through problems like this. Probably cost you less than $50 US.

    2) There are a couple Cadillac techs on this board that have intimate knowledge of Cadillacs and their quirks. I would email them directly. They may have seen this before and give you detailed suggestions. My neighbor works at Cadillac and he knows these cars inside/out. He's seen it all. He's been a big help on these.

    3) Definitely make sure you have a solid Ground. Add a new ground strap if you need to from the ground to the engine and the frame. It doesn't have to be from Cadillac to be effective.

    4) There are numerous modules behind the back seat in the trunk. One of them is the Air bag module. All of the modules reside on a common communication link including the PCM (main computer). If there is a bad connection, it could be affecting the flow of information. On the other hand, it's possible to have multiple module failures. This is why you need a Service manual so you can narrow it down. One module failure can cause misreadings from other modules (according to my neighbor). Also, according to my neighbor, the PCM is pretty robust on these cars. They don't go out too often.

    5) After ensuring you have a good ground, I would wiggle all the connectors on the modules benind the seat and the PCM down by the passenger's side feet to ensure you have a good connection. Might also wiggle connections at the dash cluster. I would probably disconnect the air bag first to ensure it doesn't accidentally deploy (remove fuse in engine comp & unplug yellow connector under steering column).

    Where do you live in Germany? I have relatives there. Been there many times.

    Mark G

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    Grizzy is offline Cadillac Owners Member
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    I have a 96 deville (concours) with digital dash and my symptoms are as follows:
    Dash started going out after going over pothole or some bump in road, then after a few minutes would come back on and stay good for weeks at a time. Lately, it is off more than it is on. I do notice that if the weather is warmer, it seems to be on when I first start the car, otherwise, in cold days, it is off and I'm lucky if it ever comes on while I am driving it.
    Does it sound like a problem with the ground wire? Apart from the cadillac dealer, there is only one place nearby that works on cadillacs and I am afraid of getting ripped off. I do have a mechanic that we use for our foreign cars, but he is loathe to work on domestics and has no experience in cadillacs. I figured, though, that if I could explain to him the thing about the ground wire, he might be able to work on this feature for me. He does have experience on working with many other cars such as BMW and Mercedes, do any of these have similar digital dashes that might be similar to fix? As you can probably tell, I'm just a girly girl and have limited (read no) experience on working with cars. Thanks for any help.

  16. #15
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    devilleconcours100 is offline Cadillac Owners Fanatic
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    Re: Digital Dash Repair Tips - Ideas how to resolve speedometer and cluster problems

    My latest car, a 1981 Seville, with the digital instrument cluster option, has some problems. For one the Diagnostic will not work, and I tested the fuses and they are all fine. The car is on when I try and I hit off and warmer and she will not show anything, however it controls HVAC perfectly. Secondly, I am having a problem with the fuel system gauges. The gauge says -- on fuel range, and gallons in tank. She also has a blank MPG Sentinel. I have never worked on a digital dash before, so I would really appreciate the help.
    Thanks, Dave

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