2003 Carrera 4
62,000 miles
never been wrecked or raced

Help!

I am going absolutely crazy. I have now replaced the instrument cluster for the third time in less than one month.

The clusters have been acquired from reputable dismantlers, programmed and installed by the dealer, no engine/charging faults determined.

Then within a few days, the two replacement clusters exhibit the same symptoms as the original unit. Gauges go crazy and then simply freeze up and dash lights go out. The only remaining part of the cluster remaining functional is the digital odometer and outside temperature display.

This is becoming an expensive nightmare and so I am seeking any feedback as to what might cause this. Could it possibly be some electrical spike from the alternator or voltage regulator that destroys the circuitry, which does not show up in the diagnosis?

I do not want to spend another $1,000 when the incident will probably repeat itself.

 

Do you not think that you may have a short in a wiring harness on the car and that is what is causing each of the clusters to fail?
Pete

 

Has to be a short somewhere that is frying the clusters.

 

Wouldn't a durametric help spot errors in power? If you can spot the alternator messing about or diagnose from which regions have the erros reported you should be able to figure out which branch is feeding the problem. I had a 64 mgb in high school and that thing had positive ground. I doubt england still uses positive ground.....wouldn't be a british model I'd figure anyway. I'd buy a durametric before letting it get away with that trick again. Ask them at their website if their stuff will extract info you need to spot the problems source.

 

Nope. What others have said. There's a short. More accurately a wire has some insulation scraped away or is caught under a bolt head or between a bracket and the dash and some movement of the car results in this wire making some sort of electrical contact (to ground or to a 12 volt hot wire) that results in a fried instrutment cluster.

These wiring problems are very hard to solve. I expect for you in order to solve this one you'll have to remove the dash and as much hardware under/behind it and examine all wiring for any signs of any possible problems.

Trace any and all wires and wiring harnesses as far away from the dash area as you can. The problem might lie just beyond the are where you think it lies.

Sincerely,

Macster.

 

I feel ya man. My odometer and temperature outside are fried. Maybe if we join both of our cars, we will have one complete?

 

you might be money ahead to get a pro shop to fix this for ya.. someone chime in a shop for him

 

These can be really hard. As Macster said, tracing each wire is often the only solution.

This assumes that:
- either something was done wrong during the car's build
- there has been unusual wear, or
- some mod has caused this -- either by inappropriate wiring or fastener that caught or damaged a wire.

Since this is not common, it might be worth it to review any mods that have been done to the car (even if they're non-electrical) and look there first.

 

I would check fuse sizes on that cluster (make sure the fuse is to spec).... If there is a short, the fuse should blow... not the cluster. Cheaper to replace fuse BTW....

 

Greetings:

Thank you for all your input. A couple more facts about the situation.

* As far as I can tell, there is no fuse in the cluster itself. I have had it apart and see no fuses in the instrument cluster.

* The clusters went haywire when I hit a rough patch of road or bump, with the first going out after going over some railroad tracks.

* I have checked and rechecked the fuses in the fuse box next to the driver side door. All are to specification and none have blown. So, the malady seems to bypass the fuses.

* Before installing cluster #3, the dealer's mechanic checked the alternator. He indicated the diodes show some wear, but does not believe it to be extensive enough wear to throw an electrical spike that would fry the cluster. And, no other electricals indicate any problems.

So, I suspect I am going to have to bite the bullet and have my independent mechanic start tearing the car apart to figure if there is some loose or frayed wiring.

Any other suggestions would be appreciated.

Chris Stocker

 

I'd seek confirmation the cluster circuit not protected by a fuse. This seems wrong to me. Let me check...

In the meantime, the info the cluster went out/haywire after car encountered rough road strongly suggests an electrical contact is the source of the problem.

I'm not knowledgeable enough to advise you beyond generalities but this suggests if you could hook up a voltage/amp meter to the instrument cluster circuit -- the instrument cluster does not have to be present -- and with the key on to power this circuit moving whatever wires/harness and any thing under the dash you can and observing the meter dial you might be able to match up touching something/wiggling something and seeing the volt meter needle react.

You almost certainly will have to remove some hardware once you've located the suspected wire/harness and to gain better access to these potentional sources of the problem you might be better off removing the dash to begin with. As I started out with: generalities; I'm short on specifics.

Sincerely,

Macster.

 

While I don't have the car in front of me, nor the wiring diagram, I'm pretty sure there's a fuse, maybe two, associated with the instrument cluster.

You need to locate a fuse diagram for your car. I consulted with one for a 2001 model and found in Fuse Holder B, fuse #S1, B1 "CLUSTER TIP BUTTON PSM PSM DIAGNOSTICS POWER TOP" and in S1, B18 "INSTRUMENT CLUSTER DIAGNOSIS HEADLIGHT VERTICAL AIM-CONTROL".

And in Fuse Holder E, fuse #S1, E1 "TERM/86S CU ALARM-CL/RADIO/CLUSTER/INFOSYSTEM/CU SENSOR OVERTURN/DAYTIME RUNNING LIGHT".

In this particulare model car one of these fuses protects the instrument cluster and the protection may be split between 2 possibly even 3 fuses.

Same in your car. Though the fuse holder and fuse number and groupings may be different.

Sincerely,

Macster.

 

According to the 996 Essential Companion

Row B Fuse 1 = Instrument cluster (15 Amp fuse)
Row B Fuse 10 = Instrument cluster (15 Amp fuse)

 

As a second update on my ongoing saga of three instrument cluster failures in less than two months, my problems still exist with no solution in sight.

I took the car to the Porsche dealer, (Rector Burlingame), who installed and programmed the previous two replacement clusters. They were unable to determine the root cause of the problem.

I then took the car to a reputable auto electric shop, whereupon they spent approximately 12 hours utilizing their extensive experience and Porsche diagnostic equipment to diagnose the root cause of the cluster failure, ($1,500 out of pocket). Unfortunately, after an invasive investigation, (dash removal, tracing wiring, sensors, fuse block analysis, etc.), they were unable to identify any issues, (alternator, wiring, fuse block, harness, charging system, battery, cluster connectors, etc.), which would cause repeated failures.

I then took my car to my independent shop to see if they could attempt to sort out the issue. Apart from the cluster itself no other fault codes are present. They also contacted two other Porsche dealer service managers, (apart from the one I initially took the car), explaining the issues and as expected, they too have never had any other Porsche of any model experience similar recurring malfunctions.

I subsequently wrote to Porsche North America for a second time replaying the history of the issue, which includes nearly $5,000 spent to date and the Porsche dealer, independent auto electric shop and independent Porsche mechanic unable to diagnose the problem.

I stressed it hard to believe my car alone among thousands of late model 993/996/997/Boxters is the only one experiencing similar multiple instrument cluster failures, requesting the issue be referred beyond customer service to their technical department to research their database to determine if similar incidents have been reported and how the issue was remedied.

Their response was to inform me that the car was no longer under warranty and therefore they bear no financial responsibility to remedy the problem and that I should take the car to my local Porshce dealer.

Most irritating, I was not asking them to assume any financial responsibility, but only to help in its diagnosis and identifying a solution to this problem.

So, it appears I am resigned to driving the car sans any gauges as I am loathe to purchase and install another instrument cluster as the likelihood of failure is high.

Has anyone had any luck in the past getting Porshce to assist in determining a problem their dealers have been unable to resolve?

Your feedback would be appreciated.

Thank you.

Chris Stocker

 

Typical Porsche response. They are just covering their *** and never want to acknowledge any on going issues.

I would check all the grounding points on the car, clean them and re-tighten them. There is an article in the latest issue of Excellence on Porsche electrical systems and common faults. While there is nothing specific to the problem you have been having, they do talk about bad grounds and the problems these cause, and how ECU's get burnt out by bad ground. The fact that it seems to happen on rough roads could indicate that a ground is vibrating and arcing. There are a lot of ground points on these cars. I will try to look and see which ones are closest of more involved with the instrument clusters.

Seems to me that if a dealer sold you the cluster and installed it, it should be covered under some sort of warranty.