FLYVMO

After about an hour searching for procedures on how to test the digital instrument cluster, the only one I have found is a snippet from tech bulletin 9302. Yesterday I powered up my instrument cluster but the information display is dead. I have changed all bulbs, and the only "life" I get in the cluster when following the tech bulletin is "Brake Light", "CAT" and 2 other warning lights along with the high voltage lamp and voltage indication on the volt meter, and the low gas light.

I have triple verified the bulbs, and the bulb traces, but the information display does not light up to show the mileage. Is there another test one can do to check that part of the cluster? Or is this the dreaded board failure?

Cheers!
Carl

Randy V

If you are powering up per the tech bulletin that should only illuminate the mileage sector.
Pretty sure you will need to power up another terminal block to illuminate the entire display.

Alan may be able to provide additional guidance.

FLYVMO

Thanks Randy,

Not even the mileage sector is lit up. None of the 3 display "windows" show any information.

Cheers!
Carl

928Myles

Carl,
there is a procedure where you can put a jumper in the round diagnostic port (by the passenger seat on RHD cars - not sure where it is in the LHD cars) that allows you to read all sorts of info testing sensors throughout the car (temp, revs, oil press, voltage, fuel guage etc). This might trigger the display - or not.
The tech bulletin is labelled "928 S4 '89 - Diag of the Instument Cluster" on CD 1 of the Moorhouse set. Porsche number WKD 495 821.

Hope this helps,
Myles

Alan

Carl - are you focussed on testing it out of the car? what was the behaviour in the car? did something happen to damage the cluster? what happens if you reinstall?

Alan

FLYVMO

I wanted to test it out of the car to make sure it worked. Since I am currently installing the ISIS electrical system it is not possible to hook it up in the car yet, so I wanted to do as much prep-work prior to install as possible. It is a used cluster from 928International since the GT shell did not have a cluster when I bought it. I was told it worked but I am curious as to why the mileage does not show up as it is supposed to. Of course it is already past the 1 year warranty...

Cheers!
Carl

FLYVMO

Myles,

Thank you for the input. I do have the diagnostic bulletin for it, but the electrical system and wiring is not complete yet. I was mostly worried if the Porsche procedure for reading the mileage didn't work, then it may be something seriously wrong with the cluster. As I mentioned in my reply to Alan, it is a used cluster from 928 International, and I was told it worked when I bought it. It has been sitting in my closet since I purchased it so it hasn't been in use since the purchase date and I didn't think of testing it when I received it.

Carl

Alan

The connections specified are just the pimary power connections to the pod (battery+, ground and ignition - as if the ignition is on). No other connections are made but the pod should do a basic power-up. I'd have expected to see power also applied on pin 1 of plug 4 (the left most connector in their diagram). Maybe try that too.

Alan

FLYVMO

Thanks Alan,

I will give that a try. As always, I greatly appreciate your expertise and helpful suggestions.

Cheers!
Carl

FLYVMO

No joy on the additional connection, the diagnostic displays are still dead. The cluster does extinguish the warning lights after a second or two except the low fuel and "Brake Light", but it tests no other bulbs. All bulbs are tested before and after install so something is not quite right.

I did get a wonderful offer from Mark Anderson saying he will stand behind the purchase even though it is beyond the one year warranty. That is what makes it a pleasure to do business with him and is what makes this community so great.

Cheers!
Carl

Alan

Do you have any illumination lights on? you should have I think (these aren't all LED conversions are they?)

Alan

Rob Edwards

Carl, if you're not averse to shipping it, I could pop it into my GTS and test it, and if it's TU could drop it off at 928Intl.

FLYVMO

No illumination (no backlight) lights are on. Test was done with both the original incandescent bulbs and LED's according to Ed's instructions. No difference in operation. Seems that after your suggestion about connector 4, the cluster does a selftest (about 1.5 seconds) of some bulbs, but not all. But the mileage counter window and the other two are dark still.

Tom is sending me a replacement cluster to help troubleshooting, hopefully that will narrow down the fault. The cluster is hooked up to a bench top power supply and I have the connectors hooked up in the back and powered according to the tech bulletin. The only thing I do not have connected is the diagnostic stalk (cruise/wiper/turn assembly). Do you think that would make a difference in getting the mileage window to light up?

Cheers!
Carl

FLYVMO

Rob,

I appreciate the offer, Tom is sending out another cluster to troubleshoot with, to narrow down what component might be at fault. Thanks again for the offer, shipping it would not be a problem. I'll see what the replacement cluster does and if still no luck I may take you up on the offer.

Cheers!
Carl

Alan

No it shouldn't be required...but gives you more options if it is.

Alan