Get a kick out of this....

[Scouser]

So, I have been having problems with my electrics.

Situation was this:

Lights off: when I put my foot on the break pedal the front left side light would light up as well as the stop lamps.

Lights on: when I put my foot on the break pedal the ABS and PSM dash lights would come on and stay on until I restart the car. Rear break lights worked fine. Front left light did not light up.

I have asked a few times for help here but still couldn;t find an answer. Then last week Loren kindly sent me the circuit diagram but it looked too complicated without legend info so I put it aside. But also my flipping back pulled out and I have been horizontal for nearly two weeks.

So, I decided to put the car in to my OPC and have them fix it. They rang me to say it could cost serious money as they can;t find the problem with all diagnostics and would have to start ripping into my electrics to narrow down where the fault lies but they think it needs a new ABS unit. Oh no! I said....not more problems.

While on my back in bed I decided to review/study the circuit diagram again. I noticed there was a possibility that if the rear left stop lamp had a failed earth within the bulb, it would be possible for current to pas through both elements in the bulb (stop and side lamps) and thus cause ABS/PSM faults. So I rang my OPC and said bring the car back. DOn't fix it. (in my mind I would rather pay an independent anyway).

Today, my back now better, I decided to take the rear stop lamp out and check it. Low and behold it was indeed faulty even though it still worked! Yup, both side lamp and stop lamps work but the bulb is faulty. I replaced the faulty bulb and bingo! fault fixed.

Loren just saved me a huge bill and all it was in the end was a bulb. ha ha.

Cheers heaps Loren. :cheers:

[Loren]

Glad I could help... (little bit that I did).

Hope your back gets better!

:cheers:

[Scouser]

Well, I am up and walking at least. My back never seems to fully get better nowadays :(

Many thanks Loren anyway.

Cheers

[Costa]

Lucky you diagnosed it down to an el'cheapo light globe rather than a more expensive ABS unit....

This is exactly what annoys me when the so called expert mechanics come across an electrical fault. They seem to try and fix the fault using 'Plug n Pray' techniques in lieu of actually trying to think about the problem.

This normally ends up costing the poor user somewhat for poor diagnostic skills.

I am involved in the electronics field so I may be a little biased here but it never ceases to amaze me when vehicle owners are forced to pay up for replacement electrical parts when the fault is not even fixed...

Typical Story normally follows this sequence of events:

Sorry mate, but we have changed the MAF but the fault is still present...

Sorry mate, but we have changed the DME .... but the fault is still present...

Sorry mate, but we have changed the Engine ... but the fault is still present...

Sorry mate, but we have changed the xyz??? but the fault is still present...

Hey mate, good news we have fixed the fault - it was a light globe... a dammed expensive one at that!

Cheers Bernie....Hope you are feeling better!

Edited April 11, 2005 by ZX7R

[Mitty]

I get charged for an hour diagnosis for the horns not working. They (OPC) say my horns are bad.

I take my car to an independent for another problem (long story, new engine when it was all over (rod bearing)). When I get the car back the horns work! I asked them what they did, they said “replaced the fuse”.

[0586slb]

Situation was this:

Lights off: when I put my foot on the break pedal the front left side light would light up as well as the stop lamps.

Lights on: when I put my foot on the break pedal the ABS and PSM dash lights would come on and stay on until I restart the car. Rear break lights worked fine. Front left light did not light up.

I have asked a few times for help here but still couldn;t find an answer...

...I noticed there was a possibility that if the rear left stop lamp had a failed earth within the bulb, it would be possible for current to pas through both elements in the bulb (stop and side lamps) and thus cause ABS/PSM faults.

<{POST_SNAPBACK}>

...Consider the following:

From the fuse, power goes through the brake light switch, through the lamp, then to earth (and back to the neg terminal of the battery. From the tail-light cluster, all the lamps in the cluster have their earth side joined in a bus bar, then a single (brown) wire takes it to earth.

If this earth becomes a high resistance path, (loose wire or corrosion or something) the current now flows from fuse, brake switch, brake lamp, earth bus bar (NOT to earth at this point) tail/sidelight, back up the wire to the sidelight at the front of the car and down to earth there. This explains why the front sidelight will illuminate.

When you switch the sidelights on, again the sidelight can't find its earth in the rear cluster, so this time the current backfeeds through the brake lamp, up to the ABS/PSM module, whereby it will cause the module to think there's a fault (The ABS/PSM module monitors whether the brakes are being pressed from the brake lights, hence the module is downstream of the switch, and will be affected by the backfeed)

<{POST_SNAPBACK}>

Do I not get an itsy bitsy teensy weensy little bit of credit? :huh:

[JimPDX]

So, I have been having problems with my electrics.

Situation was this:

Lights off: when I put my foot on the break pedal the front left side light would light up as well as the stop lamps.

Lights on: when I put my foot on the break pedal the ABS and PSM dash lights would come on and stay on until I restart the car. Rear break lights worked fine. Front left light did not light up.

Glad to hear it worked out for you. The more I hear about the way Porsche Service centers handle 'difficult' fixes, the more I am convinced that official Porsche service centers have become more and more lazy. Each post that complains about their inability to fix a problem unless they can charge more and more money is getting very serious. How can anyone go back to a dealer that doesn't take the time to read a schmatic and understand something as simple as a grounded lead. It is just getting frigging unbelievable.

I for one have no love lost for any Porsche Dealership service center.