Question
ECC Display
I have a 86 caddy sedan deville, my ECM buttons all work but the display never changes. Its showing -188* and all symbols displaying. Its as if the display is stuck. Like i mentioned, all button controls function properly but the didplay never changes. Therefore, i wont be able to read codes, etc.. What should i look for first to correct this problem?? Thanks in advance
AnswerHello,
What we are dealing with is very old electronics. When I say that is that you are dealing with plastic circuit boards that expand and contract in severe cold and severe heat. Couple that with vibration from crummy roads and circuit boards crack.
These plastics were never designed to last 30 years. We had them fail when the vehicle was new!
My guess would be the display unit, but if you don't want to go with a guess, I suggest acquiring a factory service manual. You should be able to find one for $100 or less on EBay or Craigslist. The manual has diagnostic flow charts for diagnoses and it will help you in the future for other problems. Without it you are working in the blind which can be frustrating and expensive.
As for the codes, there are scanners that will read the diagnostic codes. The system was very primitive and the codes are very general and the standard used in today's vehicles wasn't implemented until the 90s. In the newer system OBD II a problem in the computer system can be pin pointed. On your system, you can only display a circuit that can have so many issues in it and very difficult to diagnose.
Again, that is why you need the service manual.
In the event it is the display, you will have to go used and hope there aren't issues with it.
Let me know what you find.
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