'84 GL Digidash fun

[Idasho]

Any digidash experts on here? A search yielded very little.

 

Ive got a problem with my digidash clock, that is built into the trip computer.

 

Sometimes it is fine, will work for a few days without problems.

 

Then the clock will beep, and then the HOURS on the clock will start changing..... 1, 2, 3, 4..... 12, then repeat

 

Once it starts this, none of the buttons on the trip computer will respond. If I shut the car off, then turn it right back on it will start up the same craziness right away. The only way I have found to reset the clock and bring the trip computer back to life is by disconnecting a battery cable.

 

According to the manual, the "digital clock" is on the same circuit as the horn and hazard lamps. Though if I pull the fuse, the clock is not effected.

 

Any help would be greatly appreciated. I have read many threads about digidash to analog swaps. Please hold those comments, as I am not interested in such a swap...... just yet.

[hatchsub]

Id say your lucky if your clock is the only thing wrong with your digidash. Ive only heard of one or two other digi dash's that actually still work.

[Turbone]

I think thats the start up from factory sequence. Theres a way to reset it so that it displays normal.

I'll need to check the FSM to be sure.

[carfreak85]

Rob, that is not normal, FOR SURE... I would suggest swapping our the digi-dash for a regular analog dash. Can be done over a long day if you already have everything needed.

[skishop69]

It's an internal failure of either a capacitor or the time/frequency ROM on the clock circuit. It might even just be a bad solder joint. You could look for a cold (cracked) solder joint with a magnifying glass, but the other two require test equiptment, schematics and experience troubleshooting down to the component level. There are still one or two places in the country that work on older digital dashes (or at least 'were' last year). Have to do some searching to find them though.

[Turbone]

I no longer have my 84 FSM, which goes into detail on the "test program".

Maybe the digidash guru carfreak can look it up for everyone.

I do have a troubleshooting schematic tho.

 

[carfreak85]

Until someone with an electrical engineering degree sits down and fully maps one of these things, my suggestion is to ditch them. The dash wiring harness and analog console both bolt in and you can always save the digi harness and cluster for the day someone figures them out. Until then, they are the most unreliable part of the car...

[Idasho]

Im thankful for whatever help you guys can offer me. This GL is clean enough that I intend to keep it as stock as possible. That said, swapping out the dash is a terrible option at this point.

 

After reading many threads on the forum about electrical problems, and seeing how many are due to bad grounds, I added a ground this evening, in hopes of preventing any further damage. If the damage is related to the electrical system at all. Ive got a fresh ground from the alternator tensioner to a strut tower bolt now. Though, as clean and rust free this car is, I REALLY doubt the grounds are suspect.

 

Further investigation into my trip computer, I have found that the BEEP I get is simply the BEEP the computer makes any time you select a mode. So at this point I am thinking it may simply be a faulty button, or a sticky one. I know that computers will do WEIRD things when you depress a button and hold it..... indefinitely.