takovr

Here is my story, I own a 86 corvette with the digital dash. About a year ago it started flashing on and off. I would start my car it would lite up for a wile then go black. Some times if i taped on it it would lite up again but for the most part it would just turn on and off. I decided mail it out and get it fixed, the company replaced the pwer supply unit in the dash and all of the bulbs. I got it back and put it in my car and it worked for about 3 months. Well its back to doing the same thing again. I went on the internet and found a site called batee.com i tried some of the sugested fixes like i ran 3 new ground wires to another ground but dash still does the same thing. Is there a way i can remove it and check power to it to make sure it is working? I could really use some help with this problem....

corvetteronw

Dang, that sucks. Might be time to go analog:
http://forums.corvetteforum.com/c4-t...cluster-2.html

HlhnEast

Do your gauges work but no backlighting?

Oh and BTW the on board power supply is for the LCDs not for actual backlighting. The power for the lights comes from external sources.

takovr

All of the gauges work, but dash is dark.

jman4582

I'm actually having a very similar issue with my '90. The speedometer lights fine but all the other gauges typically stay dark. Just like takovr, if I tap on it, sometimes they light, but they're usually dark. I'd appreciate any help as well.

HlhnEast

(Big Breath)

OK well first you hafta check the external inputs. Check the INSTR and TAIL fuses. Good? OK before putting them back check the blades for battery voltage on one side. Good? OK it gets more complicated. Remove the digidash. There are two connectors a 24 and a 32 pin. On the 32 pin connector there are 3 battery voltage pins. The side with the black ground is D. Check D16 and across at C16, should be bat voltage with key in run on both. Pull the lights on and check C6 for bat voltage. Good? OK youve eliminated wiring issues and the headlight switch as problems for + input.

You said you ran new grounds to the 3 black wires. Did you check the job for resistance after the fix? With a multitester check resistance at the black wire pins on both 24 and 32 pin connectors. It should read very low resistance, almost like touching the two probes. Good? OK youve eliminated the ext. ground as a problem.

Now it becomes very complicated. The issue is with the digidash itself whether it is a bad solder joint or bad connection at the ten pin connector that joins the two circuit boards. I got lucky with mine the problem is obvious I had a bad connector pin that was marked by scorched looking residue and a misaligned pin. I soldered two jumpers with crimp Male/Female connectors for board separation right at the base of each pin bypassing the connector.

Check out all of these things and post up results.
Good luck

lgolson

Mine was exactly as you describe when I bought it. After I re soldered those pins on the board this was the result



These are the pins I would look for. As was said earlier, they connect the two circuit boards together.

engle1147

If all 4 backlighting bulbs are going out at the same time but the LCD are still working it is most likely the connector pictured above. As pictured above the pin on the far left is usually the problem child.

takovr

So is it possible when I sent out my digital dash to be repaired they didn’t solder the pins correctly?

HlhnEast

Engle has the culprit right the far left pin is the + side of the lighting circuit. I soldered the jumpers on the back side of these connectors. I used a 40 watt pencil well tinned soldering iron at full temp to solder them in. A quick zap and done before you heat up more than necessary.

Takovr, most likely the repair shop may have missed the original problem. If your dash is acting the same way now as it was before I would say they definately did. If your gauges worked with no lights I would say they didnt need to replace the power supply as it powers the lcd functions not the backlights.

Lgolson Thanks for adding the pics of the connector, I didnt take any pics when I did my repair. You

yaknow

As a side note, check your headlight switch, or replace it, I had issues with my 87 dash lights blacking out intermittently, replaced the swithch all was good.

HlhnEast

Power does indeed feed from the headlight switch. The check for battery voltage at C6 of the 32 pin connector with headlights on will determine if the switch is ok.

GMC_Jimmy

[QUOTE=HlhnEast;1577218934](Big Breath)

OK well first you hafta check the external inputs. Check the INSTR and TAIL fuses. Good? OK before putting them back check the blades for battery voltage on one side. Good?

- Is the INSTR fuse a 3 amp?

So are you talking about the bottom row in the middle? Because Im getting no power there

HlhnEast

Did you try it with Key on Engine off?

GMC_Jimmy

Yep both on and off, and nothing

GMC_Jimmy

Can the headlight switch still operate the headlights but be the problem? How would I check it?