Sounds like the dash itself might be going bad or has a loose connection. Schocki posted a proceedure to get the pod cover off in about 15-min. At that point you can remove the 4 edge connectors and try cleaning the board connectors.

 

UPDATE 9:18PM...Had pulled fuse 25 earlier in the evening (thanks Roger) as the digital dash had refused to quit flashing. Went back out a few minutes ago to try again, put the fuse in, digital portion lights up solid and then goes dark.

Hmmm...Put the key in, turn it on, and it lights up normal. Fire it up and I have tach and fuel. Probably safe to assume speedo as well.

I think I'll observe it for awhile and see if it goes out again. If it does, I'll probably pull the pod and clean the connections back there. For now, if it ain't broke, I'm not gonna try and fix it.

 

What just a minute... In the 928 world, I thought the motto was:

If it's not broke... fix it until it is!


Good luck.

 

LOL...BTDT!

Man, I'm just breathing a sigh of relief now. I'm not touching it for a while.

Thanks for the Schocki link, I'll log it for future reference.

 

You need to drive that car more. That's what it is telling you.

 

check the hot post connections

 

[QUOTE=Landseer;6026369]He has the best color, agreed.

Hi Jarrod,

Is that color Velvet Red? or one of the other red derivatives. Do you have the Porsche code for it.
I am thinking about changing my Indian Red paint to a metallic color, and yours looks the best I have seen.
Thanks
Jay

 

Thanks Jay. Yes, it's Velvet Red Metallic, paint code 81L. If you would like to see more pictures of it, I have a photo album of images posted on www.renntube.com under my username "928gtsfan". HTH.

 

UPDATE 9-21-09

Here's the latest on my continuing intermittent instruments and now digital dash.

After the previous update I thought everything was fine, but no. As discussed previously, all fuses have been replaced, grounds have been cleaned, hot post is tight, and the central circuit panel has been sprayed with contact cleaner. The digital dash going on the fritz came after the latter. All work was performed with the battery disconnected, BTW.

In my continued efforts to resolve, I turned my attention to the instrument pod. Using Herr Schocki's 15 minute pod removal process (thanks Schocki!), I removed the instrument panel and cleaned the contacts on it's circuit board and sprayed contact cleaner in the 4 main harness connectors. I also cleaned the pod grounds. Nothing visually looked amiss, the parts were very clean, something I've come to expect with this car.

Anyway, I put everything back together, hooked the battery back up and turned on the ignition. Instruments were still no go, and the digital dash was still flashing.

Here's where it gets interesting. I normally keep the pod adjusted fairly low. On a hunch, I loosened the adjustment lever and moved the pod up and down. Voila! The instruments came to life and the digital dash resumed normal function. Anyone have a clue what this could suggest?

The four main harnesses are firmly seated to the instrument circuit board and their respective levers are in the locked position. The bundle of pod ground wires are clean and tightened down. I'm at a loss.

I really want to get this resolved, as I don't want to lose the digital dash (and thus the odometer) while I'm driving. Losing speed and fuel are annoying, but the digital dash has these functions as long as it works. So far, the digital dash issues have all happened, and been cleared, while sitting in the garage.

Thanks in advance!

 

Sorry I didin't see this thread earlier.

I had a similar problem with my 90' S4 when first purchased. That was a while ago, but I seem to recall the non-ops were: speedo, fuel gage, cruise control, and headlight pop-up. Anyway while driving the car, by chance, I happened to notice if I jiggled the ignition key everything came back to life.

Replaced the ignition switch and no problems since.

 

Thanks for being about 2 weeks ahead of me on this lol! Same deal on my 89, except my digital dash is just blank instead of flashing, the spedo, tach and fuel guage never wake up, the oil pressure guage *sometimes* wakes up a little and the voltage guage always works perfectly (!).

My attack so far: I've pulled the cluster and checked the contacts, no avail. I checked ground point IV (on the steering column) and it is fine. Next will be checking/cleaning fuse 25, checking the undercarriage strap, pulling the cluster again to clean all the contacts and check for proper ground on the connector and finally resoldering any pcb to copper connections on the board.

Not a hijack, just an FYI and I will post what I find as well. Good luck.

 

Sounds like there's a broken or frayed wire - probably at one of the pins in some plug in some part of the pod.

Modulo some further thought, this is what I might do:

- dispense with the quick pod removal and remove the pod totally.
- reconnect everything; you can balance the cluster on the steering column.
- reconnect the battery
- adjust the steering column until you have dash function
- then....

start, carefully, wiggling wires as the would wiggle if the pod was moved. Hopefully this will result in the identification of a specific wire bundle to examine.

Alternatively, the symptoms seem consistent with a power or ground issue. Although you probably want the pod completely off when you do it, you could - using the wiring diagrams - examine each wire/pin that is ground or power to the cluster. And of course, the wires to the ignition switch as well.

 

Mine is fixed. Fuse 24 ("Diagnostic Connector; Current Pulse Tailgate; Interior Light". Intuitive!) was blown. Put a new one in - pop! Turns out the back seat interior light plastic broke (3rd one to to this) and was shorting out the circuit. Strange in the way it brought the dash display down (see my original comment), but hey it's working now. Just my update, glad yours is working now too.

 

Having just spent the past 4 hours trawling my way through loom after loom after having the same issues, same as Bundy traced the fault to the rear interior light unit.

Now all ok, if in doubt disconect it and see if the fault re-occurs. Due to the age of the light the plastic has reached its life end.. time for a new one.

 

Do you mean the rear interior light in the ceiling? Or the one in the hatch lid?
I am asking since I have the same problem: no speedo, cruise control, fuel gauge and no tacho... I have been checking most electrical connections. I will be re-checking all ground straps after reading your posts, but I had not made a link to the interior lights yet. All my interior lights work fine, but could it be an issue?
Leo 1984 928 S2 euro manual.