0586slb

Berny, Sounds like the old bad earth chestnut again. You would see this on old F*rd Escorts from time to time. I suggest it is in the left rear cluster, as it is lighting the front left lamp. (Sidelight, I presume??) 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) Conclusion, check the resistance of the brown wire in the cluster to a metal part of the body, in the left rear. (but I would check both to be safe) 0586slb Newcastle, UK (*Nearly* Capital of Culture 2008 - Scouser will understand this!!)

I'm getting all four of my tyres changed next week, Michy Pilot N1s. I swear by them, I've always used them because I feel that they outperform most tyres in the wet. (I have them on my Golf GTi, A4 1.8T Sport and my Boxster S) Incidentally, how much do you guys pay for a 265/35 ZR18? Prices here are roughly £250 each, thats about $500 (with the current exchange rate) each for a Pilot N1.

The e-gas throttle bodies are a servo controlled motor operating at a PWM controlled (5V or 12V - I can't remember) to drive the motor with dual opposing feedback potentiometers. The ECU provides a Pulsed Width Modulated 5V signal to drive the throttle. So if the throttle needs to open quickly, the pulse mark-to-space ratio will be large and the butterfly will move quickly. If the increment is small, very small pulses will be provided to make precise movements. The pulses are a positive or negative voltage - depending on which way the throttle butterfly has to move. The potentiometers feedback to the ECU the exact position of the butterfly, so the ECU knows how many more pulses it needs to deliver to get the butterfly to where it wants it to be. (This is the principle behind servo control, without going into horrendous hysteresis and overshoot/backlash considerations...) The potentiometers are duelled, one increases its output and the other reduces and each value is fed into a separate microcontroller inside the ECU. Each microcontroller compares the results with its companion, and if there is a discrepancy, the throttle is shutdown into the 'limp' position and the lamp lights on the dash. (System redundancy) The throttle pedal again has two potentiometers opposing, and acts in the same way.

Boxster S 2002, UK RHD, *just* before facelift model. Is it possible to retrofit the glovebox to the slightly earlier model? I'm crying out for extra secure storage space in the car.

I can understand you may not have the resource to go to the Porsche dealer, also they seem to have mis-diagnosed it for you. Have a go with Customer Care, they may surprise you!! But I'd still advise a professional independent. They should have a 'sniffer' probe that loves the smell of refrigerant gas, and can find very small leaks. I am in no way judging your ability to do this, but here's a few A/C facts to help your gamble: 1. PAG oil. Too little, or introduced in the wrong place, compressor seize. Too much, hydraulic lock in compressor or clogged receiver/drier. 2. The system works by passing liquid R134a through a tiny hole (restrictor) so it vapourises in the evaporator thus causing a cooling effect. Any dirt introduced to the system, will clog the restrictor. Any water vapour introduced, can freeze in the evaporator - and clog the system. To repair a clogged restrictor, its in the evaporator thats buried as far within the dashboard as you can get! Leak Stop - doesn't that try to block tiny holes...? On a lighter note, I had an old F*rd a number of years ago that was constantly needing topping up with coolant, I discovered a small radiator leak. In went some 'Rad-Weld' solution into the expansion tank. After a few weeks of driving, the level in the tank never moved, but the engine still boiled dry!! The Radweld had formed a solid goo in the exit pipe from the tank.

You did not mention why you are considering buying this kit. Is it because you feel the A/C is not getting cold enough? Have you had it diagnosed as being low on gas? Have you opened the A/C circuit to change a component? Its not really a DIY job. I presume the "kit from eBay" is just a bottle of R-134A and an adapter that you hope will connect on to your service valve? There could be many reasons that the A/C is not getting cold enough, these can only be effectively diagnosed at the dealer or by professional A/C engineers. If your A/C circuit has been leaking, chances are that the refrigerant oil has been leaking too. If this is the case, the A/C tech has to fix the leak, work out how much oil is in the system, evacuate all the old R134A, flush with liquid nitrogen, evacuate again, then refill with a combined mixture of R134a and PAG oil. Which service valve do you use with the kit? The high pressure or low pressure one?

Paul, I've just joined the forum, did you solve the problem? I can say that the contacts used in the switch for the DRLs or sidelights are a different contact entirely to the one for the Litronics. You say they flash like old fluorescents, if the arc does extinguish, the ignitors will pulse to re-strike, but this will be random and each side will act independently. Your symptoms suggest an intermittent high resistance, likely in the switch but not definitely. Without getting too technical, its to do with contact whetting - that is - a contact may have a high resistance, but once you can get a current to flow, its resistance drops. This is achieved by you flicking the light switch on and off. Remember, it could be in any one of the components from fuse, trough switch, all the various plug couplers until it splits for each headlight, as both flash together. An autoelectrician with a multimeter should be able to trace the voltage through the circuit fairly quickly. If all that fails, there *may* be a problem with one of the headlights, where a faulty unit could be shorting the power from the other, but you'd hope a fuse would blow if this happened. Give us some feedback of how you get on!

I've just joined the forum and I'd like to share my experience. All of this information would ave been invaluable to me some time ago. You've got permission to laugh as I now can see the funny side... Last year, out to the local supermarket in my 2002.5 Boxster S. It was winter time and when it rains in England, its whole water! Just as I was pulling in to the car park, the warning lamp for the top came on. I thought the top may not have been closed properly so pressed the button. Nothing. Ah, yes, unlatched the top-lock, pressed again. I realised that I'd pressed the wrong side of the switch only when the clamshell was fully open and the roof was open 4 inches! The light was now out on the dash, tried to close the top but wouldn't motor closed. (Would still like to open though) Rain lashing down now, 8 miles from home, 10 miles from the Porsche garage. Decided I would try to drive to the Porsche garage, but even at 20mph, holding on to the roof handle it was trying to lift me out of my seat (rain still pouring in, windows down halfway as well, remember). Just then, red and black ball joints flashed through my mind, as I'd read the emergency procedure in the manual when I got the car. I managed to take cover under a filling station roof and set to work, with onlookers that couldn't move for laughing. It felt quite a brutal experience when popping the balljoints off, red ones came off OK but felt something would really break when trying to get the black (clamshell) ones off, so removed the spring clips instead. Dignity and watertightness restored, I headed home. A few days later, the top was fixed in a couple of hours at the Porsche workshop (under warranty)