uncre8tv

Before I tear into the cluster, want to confirm it's the smartest step:

I've got no digital readout at all, no speedo, no tach, no temp, no fuel. I DO have oil pressure and voltage. I also have parking brake, abs, and turn signal lights operating normally. Also the gauge illumination seems normal.

So, given this, is it likely the issue is behind the cluster, or down in the dash/fusebox/etc? I am also in a non-starting state right now (suspecting bad LH but still working through Temp2 and grounds to be sure) so grounds everywhere are being checked.

Most gauge issues here talk about one or two out. The one post I saw with identical systems did not have a resolution (may have been another board I saw that on)

So.. tldr; anything I should check before pulling the cluster?

John Speake

Check all the fuses - there are several that are linked to the digi dash.

FredR

Notwithstanding John's post on fuses- I doubt that your cluster would fail on such items simultaneously so logic suggests either you have the common age related terminal strip degradation problem [cluster out to rectify] or maybe some rodent has had a good nibble on part of your wiring harness.

The terminal strip blocks on the central electrics can also cause similar random problems and not uncommon to have issues either end at this age.

The engine should [I think] start even if you have major dash panel problems as it is not doing anything diagnostic/control wise that I am aware of- just a visual feedback of status conditions to alret the driver as to what is going on [or not].

Pulling the VDU and cleaning the terminal strip is one of those inevitable [sooner or later] things you have to do and probably not done previously in the 25[?] years since it was put there so a good input investment irrespective of root cause. Remember in the car age scale 25 years is probably about 100 in human terms! If my body was doing as well as my 928 is I'd be a happy teddy [not that it is doing too badly].

Regards

Fred

DR

Check fuse #24, especially if your interior lights are also not working.

If so check all the interior lights for a short which is usually what causes this.

Cheers,

Dave

Landshark87

SIMPLE THINGS FIRST!

i disassembled the entire rear wiper mechanism on my old 928 because it wasn't working .... only to find the nut at the base of the wiper arm was loose.

Alan

Check fuse 24 as already noted by DR - AND check fuse 10 both feed the digidash.

Multiple things heading out at the same time sounds more like a single point failure - not just general degradation - so if you weren't in there doing anything start elsewhere...

BTW in this case 'check' does not mean replace the fuse - it means test the fuse, if needed replace it and then test the fuse again... you may have a contining issue you need to debug.

Alan

uncre8tv

Thanks all! Heading from work to a soccer bar, so probably won't tear into it tonight. But I'll check fuse 24 for sure and go from there... (good point on the note that eventually the terminal strip will need cleaned either way.)

uncre8tv

Fuse 24 did it! ...for about 30 seconds. Popped when I shut the door.
so... likely shorts? Looks like it's the dash, plus the interior lights (all of 'em?) plus the hatch popper? Any first-hand experience with shorts in this circuit??
Since it seemed to pop when I shut the door, I figure I'll start with that door light.

Also, he decided to start today. With no intake on, revved it lightly in the garage for a minute or so.

Also got my drivers side mirror glass fixed (3rd party internet mirror glass, cheap but the right size) so it's sizing up to be a good day.

Mrmerlin

what was the last thing that you fixed?
I will bet its related.

Might you have tried the hatch pull and then it failed the pull switches can fail ,
some carpet thread wrapped around the tip of the pull rod will fix the switch
were you working on any lights?

Alan

It is most likely the interior lights. Most likely the ones in the roof and hatch - since they are surrounded by grounded metal. Remove all of them and inspect - with the wires out and everything disconnected test fuse 24 again - does it still blow? if no it was the lights - work though which caused it - usually its obvious (and was the one that didn't work properly).

The lights must be connected correctly - on all of them brown is the frame connection. Red (front) or Green (rear 2) goes to the bulb direct connector. Brown/White (front) or White (Rear 2) goes to the switched connector.

Alan

uncre8tv

Going to check the dome light. I just bought the car Saturday and #24 was popped when purchased. (which was convenient for the PO... "somewhere just over 100k" turned out to be 117k when the fuse was in! ... caveat emptor)

uncre8tv

great info, thanks!

uncre8tv

Hatch light crumbled to pieces when I pulled it out (front light looked like it'd been pulled out a few times too.)
VW replacements, or OE?

just how the hell many lights are on that circuit anyway?
- top of hatch (needs replaced)
- front dome (probably needs replaced)
- driver door (works)
- passenger door (bulb out?)
- driver footwell... I think? (either works or i was seeing a reflection from door light)

any others?

edit: and i did just sit in it playing with the dash readouts for a solid five minutes. gotta love toys.

Mrmerlin

there are 5 lights on the interior not including the red door lights.

1 in each door ,
1 over the mirror ,
1 over the top of the hatch and,
1 at the rear edge of the hatch.

NOTE any housing that looks melted or deformed should be replaced.

I suggest the lights should all be turned off and they should stay that way unless your going to fit LED bulbs.

Also get heat shrink and cover every connector at each light,
this so the errant connector wont find ground or short out on the power lead

Alan

And on '91 and later there is another one over the CE panel.. on a separate fuse (handy when you need to change the interior light fuse!)...

Before '85 there was only one hatch light (the upper).

I would suggest getting the replacement VW lights - I really like them - a significant functional & reliability update, and if your trim is pulling away from the sockets (common) it will hide that too...

You do need to modify the connector on the hatch end one to get it to fit (easy)

Get them from Roger (ROG 100).

Alan