Blank cluster / dash display and immobiliser killing engine - wiring help needed.

[logrover]

Hi all, great forum.

 

I have a 2009 1.4tdi BNV Fabia with 60k on it. 

 

All was running well, then cluster went blank when driving but still ran ok. Parked up fine, but when went to restart the cluster remained blank, engine fired ok, but died after 2 seconds, repeatedly. Tried jump to another good battery, same. Tried second key, and lots of locking and unlocking, same.

 

From reading on here I suspect the cluster is dead and so immobiliser shutting things down once started.

 

To help working out where the cluster issue is (power to it, or dry solder joints maybe), I plan to pull it out tomorrow and check power to the connector to see if the issue is before the cluster (fuses/relay/wiring) or go digging further inside the cluster (joints).

 

Can anyone let me know what the wiring to the connector should be so i can check earth and live and anything else? (I couldn't find a suitable diagram online yet).

 

thanks,

 

 neil. 

[mrgf]

You may be right with the diagnosis and most likely, Wino here will be of help. The only thing I could have suggested was to disconnect the battery for a short while as there is sometimes the likelihood of some of the display going off, due to a static build up and it generally returns after doing as mentioned. I am clutching at straws here, though as you are having ignition issues to boot, whereas MY experience of the problem I mention, just puts out the display. The engine still runs, etc.  You could I suppose, also have a blown fuse and/or fusible link, somewhere. I hope someone gets back to you soon!

[Breezy_Pete]

Check cabin fuses 2 and 20  16 and 22 first, before any dismantling.

Edited 12 February, 2021 by Wino

[logrover]

thanks both for replies. Quick update:

Yesterday (when fault present) I had checked all fuses and disconnected battery (briefly) and shorted battery leads together - problem remained. I had planned to try the "try starting, leave ignition on when it stalls and disconnect battery for many hours, and should be cured when battery reconnected" method.

 

However, when I went to the car this morning, the fault was gone! Dash was lit up as normal, and it started instantly and ran fine. Nice, but would have preferred to have found a fault.... I therefore removed trim and cluster, checked fit of plugs (both ok) and did a brief inspection of cluster on kitchen table (removed casing, inspected soldered joints , but didn't remove needles and faces). didn't find anything conclusive. I then did some testing of connecting each of the two connectors in turn and ignition on to see if i could replicate the fault. disconnecting the smaller block (power/earth feeds?) gave the same result (dead display). It did however throw an airbag light fault/light up, but that was cleared with a cheapo ebay VW OBD code reader which i was pleasantly surprised about having read posts about needing VCDS or dealer.

 

So with it all back together for now, I began thinking about cause. It was -11 here yesterday morning, but car started fine having been sat for a week. There was moisture on inside of drivers window which this fabia hasn't had before (rare i know, i have two other very damp fabias...). It was driven for about 10mins with heater on maximum before gauges froze and display went out, but carried on driving ok. Once stopped and switched off, it then would not restart (well started and immobiliser cut out after 2secs). Then 3hr wait for AA to not be able to diagnose and truck it home. This morning was a mild -2, and dash was lit up fine ok and so it started and ran fine.

 

So first i thought cold and damp related, but it started fine first thing both days. Then i thought heat of the heater on max, so i sat in the car for 30 mins with heater on max today and tried wiggling/pressing connector with console loosened, but i could not recreate the fault (shame).

 

That's as far as i got today. It works, and Airbag light out, but I'd prefer to know what the issue was and fix it.

 

Is it possible to provide a 12v and earth to the cluster on the bench, and then try some heat (hairdryer) to seek out any dry-solder joints? Has anyone tried that?

 

thanks.

[Breezy_Pete]

22 hours ago, logrover said:

Is it possible to provide a 12v and earth to the cluster on the bench, and then try some heat (hairdryer) to seek out any dry-solder joints? Has anyone tried that?

 

 

Pins 6 5 and 7 of the 8-way need 12V (pin  6  5  ignition 12V, pin 7 permanent), pin 8 = 0V.

That should get it going on the bench.  Don't be too startled if after a few seconds of being powered up, the piezo tweeter suddenly gives you a long blast of noise! Can't remember if it stops or continues but if you're not expecting it it's loud!

Edited 13 February, 2021 by Wino

[logrover]

thanks wino, i'll give that a go tomorrow, and thanks for the noise warning 

[logrover]

Todays update - removed cluster and had a better look indoors as too cold outside today (although dash was lit up ok and started fine so problem not evident again). 

Once on kitchen table with good light and glasses i could see what looks like a possible dry solder connection on pin 1 (front right of the 8 soldered pins on my photos). One pic shows before and one shows after i reflowed the solder. Took about 20 photos just to get these two.... These pins are small and hard to see whats going on, but zooming in on the pics on phone/pc afterwards helps.

 

Wino - On the wiring i tested the plug in the dash for earth, Bat feed, Ig feed, before I went inside and found one pin different to what you suggested. I found 8 was earth, 7 was a bat live, but the ig feed was on pin 7 (not 6). Everything powered up ok on the kitchen table, but despite some good warming with a hairdryer i couldn't recreate the fault before the soldering was done. I'm now curious what the problem pin is used for. It is pin 1 with the pinkish cable to it - do you have a wiring diagram that shows what this is used for?

 

So I'm hoping it was a dry solder joint on pin 1, and that pin 1 is something that could disable the whole display, and that I've now addressed that - but I could be wrong on any of those.....

[logrover]

Oh yes Wino, I did get that delayed buzzer going off once I supplied a two power feeds and earth - so thanks for that warning 

[Breezy_Pete]

I either didn't zoom in enough, and/or didn't have my reading glasses, because when I look again I see that the ignition 12V supply is on pin 5, not 6.

Will check what pin 1 is in a second.

[Breezy_Pete]

Pin 1 seems to be the brake wear sensor so I can't really see that being relevant.  Do you still have the cluster out?  I'd reflow all 8 of those joints, and have a damn good look at all of the ones for the green connector too.  Broken joints can be very hard to see without good light and magnification, at my age anyway!

Circuits are available to download at erWin Skoda, though you have to pay a small fee for an hour's access. If you want to do so I can talk you through the process.

Edited 13 February, 2021 by Wino

[logrover]

yes, i'd found ig feed on 5 too (but mistyped as 7 above !) - anyway, we both got to 5 in the end 

 

We did have the brake pad warn light on last week a few times, then disappeared, so probably related to the pin 1 - will keep an eye on it.

Cluster is back in, but it only takes 2 mins to take out so I'll follow your good advice and reflow all pins tomorrow as could well be 5,7 or 8 if not 1. 

Thanks for pointer to Erwin, will check that out.

cheers,

 neil

[logrover]

Whipped cluster out and reflowed all pins on both connectors - didn't take that long and just managed to get to all pins without removing needles/faceplate/LCD.

 

All back together again now and lights up and starts fine, and will test drive tomorrow and see if the mystery fault returns (could still be a fault with power getting to the cluster rather than cluster itself).

 

Thanks for the help Wino and Mrgf.