Hello everybody from a European Cadillac owner.

It would be great if someone could help me with my speedo problem.
3 month ago the digital speedo dash and the climat controll dash died. I went to my local GM dealer and they replaced the EMC, the digi speedo and the Central power source modul. I had to pay a lot of money but everything was working again.

Two weeks ago the speedo dash and the climat dash died again. I don't wanted to do a bank robery to pay the same dealer to fix the same problem again, so I searched the web and found your great forum. Some threads are suggesting to change the central power source modul or to connect the digi wire with the radio wire. So I did. First ordered a new power source modul from GM but this didn't brought me back the dash. Next I pulled out the radio and speedo and connected the yellow wire from speedo with the grey one from the radio. This operation brought me back the speedo dash glimmering on half level (good so far at night but on sunny weather too low power), but the climat control dash keeps dead.

All buttons are working. I can set the temperature and reset the trip counter. Dimmer is working too.

Does someone has an idea what is going wrong with my pretty Eldo ???

First things first: Before you connect any more wires to different components, go back to your GM dealer and get a schematic of the dash. The color codes and wire functions they provide are invaluable. Sometimes they'll just print one out for you, otherwise you'll need to buy a shop manual. (Always a good idea to have one of those anyway.)

Simplify, simplify, simplify! Break the problem into little pieces. Treat the instrumentation as a complete "system", with the various functions (cruise and climate control, entertainment, etc as "sub-systems". This is the best way to simplify what can initially appear to be an intimidating problem. Effective troubleshooting skills are a lot like detective work. Take your time and look at the clues the problem presents to you. What IS working can sometimes help you figure out what ISN'T working --that's why a schematic is so helpful--if you know what you're looking at. A second set of eyes (and brains) never hurts either. You might have more than one problem, so consider what's not working, and try to determine if there is any circuitry or "sub-systems" that are common to one another. Write everything down, as this can get confusing and you don't want to waste time wondering if you already checked something. Get the brightest light you can lay your hands on and do a very thourough visual inspection of the underside of the dash first, before you start replacing things. Sometimes, one damaged wire is all it takes to ruin your whole day. (NASA engineers will attest to this!)

When you're satisfied that there isn't any damaged wiring or disconnected/dirty connectors you can begin to get medieval on this problem. All things electrical (DC) require a ground and power, so start from there. Once you verify power is getting to the various suspect modules, disconnect all connectors to the "peripherals" (climate control, etc) and try to just get the computer to "talk" to the dash. Methodically build the "system" up until everything works. I know this sounds kind of simplified, but that's the way the pros treat complex problems, and it really works.

Once you get one section of the dash working, de-energize the electrical system and start connecting everything up, one circuit at a time, checking the operation of each as you go. One or more defective modules or "sub-systems" could be holding the others down.

Obviously, I'm limited in how much I can help you troubleshoot without a drawing in my hand, but there's a lot you can do without in-depth electrical knowledge as long as you know your limitations and don't connect wires unless you know exactly what they do. Guesswork is NOT part of effective troubleshooting, and will only serve to frustrate you and maybe cause additional damage. So if you aren't sure, STOP! Get help from an electrically-inclined friend, and make sure you give him plenty of beer --after he helps you fix the problem.

Write back with any additional clues/observations and someone on this board will probably be able to help you out; you're right --this really is a great forum, which is why I'm pleased to be a supporting member.

Good luck!

CC

Hi TomTom ............ I too am a European member (U.K.)

I too have an '87 Eldorado.... and wait for it my complete digital dash blew 3 weeks ago......... Trouble is now you have to make sure there is gas (petrol) in the tank!!......
Luckily I have a great local guy who identified a board had 'fried out'..... we are now in the process of buying up an old dash from the U.S. (cost
around $150) so hopefully between the two units it can be rectified...... may even be able to get original recorded mileage back on speedo.
So no real help really..... I can only share the problem.
Keep me posted how you get on....... I will also do the same if your interested.
Apart from above I just love it..... it's such a great ride and really looks the part especially with all the bland euro shapes around these days.
Where do you live?
Kind regards,
Mike

Hi........ Sorry....... CC forgot to mention on previous message....
GREAT ADVICE.... YOU GUYS ARE SO HELPFUL.....AM I GLAD ALONGWITH
HUNDREDS (probably THOUSANDS) OF OTHERS OF FINDING THIS FANTASTIC FORUM TO SHARE EXPERIENCE & KNOWLEDGE.
CHEERS

Hello CC,


many thanks for your support !!!

Yes, I already have been to that GM dealer asking for a schematic plan. They don't have anything for my "Oldtimer"

The situation here in Germany is : we have thousands of OPEL dealer and a 2% of them provide GM products as an aditional service. There is no specified GM dealer in Germany. The guys know to work on their ugly Opel Astra and Corsa but don't have a Tech I diagnostic computer modul to connect with my Cadillac. And if you found one, they don't know how to manage the trouble codes.

It would bee the same if you go with an Opel Astra (together with 2 sixpacks of beer) to a GM dealer in the States. They would say : Nice car but, sorry we never worked on this .

I'll go for troubleshooting myself next weekend and see what I can find out. If I'm succesfull I'll let you know,

Thanks again,
tomtom

Hello Cadillac Avenue,

I'm from Germany. Yes, a nice exotic car for Europeans we are driving. Is that only your speedo dash that is dead or the Information Center dash too (like mine).
Please let us keep posting about this problem. I think we are not the only one with dash problems on Cadillacs,

Greetings,
tomtom

Hi Tomtom,

As with you........ all has been lost........ Dash, Message Centre all digital read-out..... All Warning lights are functioning alongwith all other electrical inc radio.
Will keep you posted once the used & replacement dash from the U.S. arrives....
Have you acquired a CadillacService Manual ...I picked up one of ebay?
Cheers for now,
Mike

Hello Cadillac Avenue,

seems to be the same trouble with our Eldos. I don't think that your speedometer has blowen of. Safe the money ordering a new/used one. As I posted before I got my speedo working on half power just connecting the yellow wire from the dash to the grey wire of the radio. Pull out the front dash mask and the radio (10 minutes) and you will find those 2 harness,

Good luck,
tomtom

Hi Cadillac Avenue
Did you ever get your dash sorted as i have the same problem.
I live not toO far from you in Shipston on Stour my phone no is H:01608 665946 W:01608662354 any help would be appreciated as this is driving us round the bend.
Cheers
Duncan
Holland