Help, no electrics..................

[Paul190H]

Interesting situation today on the S2. Started fine and set off up the A32. Charging gauge seemed to be stuck on 14volts rather than a touch under although this did not concern me overly.

However, when I flashed to let someone out of a junction there was a dramatic dip in performance which was fine again as soon as the lights went out. Every time I flashed the lights, the same loss of power.

Thought it might be alternator so switched off fan stereo etc to save battery. Car got me to Basingstoke fine, switched it off and when i turned the key back on nothing. No interior light, dash lights central locking etc. looks like I'd driven the car on the alternator only?

Battery is only 7 months old and a decent Bosch. Went into meeting thinking i'd need to get her trailered back.
Came out 1 1/2 hours later and normal service resumed drove back to Winchester with no problems.
Think this happened about 5 months ago but forgot all about it.

Is there a relay that can cause this problem? One assumes it won't cure itself []
Thanks
Paul.

 

[Lowtimer]

I can't answer your question but it is not a unique problem because I have had both those symptoms, occasionally, throughout last year. Most of the time it was fine but sometimes it would crop up. However it was so intermittent that on any day when I really tried to chase it down, it was not exhibiting the fault. You would imagine that it might likely be a wiring fault somewhere in the flasher switchgear or the associated wiring in and around the steering column and ignition switch. However, ast time I had the car down at Promax they went through all that for bare patches and broken wires etc and couldn't find anything wrong. My battery was about three or four years old and I replaced it in case it had become marginal, e.g. in case reduced voltage stability meant that flashing the lights dropped the voltage momentarily in a way that upset the engine electronics. Thus far with the alternating floods and salted roads that have been a feature of the last few weeks I have not driven it much since replacing the battery but I have not had the problem recur since then either. It remains to be seen if it rears its head again later in the Spring.

 

[Paul190H]

Thanks for the reply, think it must be more fundamental, if it was the flasher or ignition area I would have had interior lights and central locking. I guess it could be the starter area or the location of the positive cable after the starter motor. Maybe an earth problem?

 

[Lowtimer]

I think it's axiomatic that any electrical problem might be earthing-related and on any car as old as these it cannot possibly hurt to clean up all the earths. But I suspect that an earthing problem would not be so infuriatingly intermittent. To me it feels more like a wire broken within its insulation, which sometimes fails to contact. Or a rubbed-off piece of insulation which ever so occasionally comes into contact with something it shouldn't, causing a short or possibly a voltage spike which upsets things. However, I am in no way an electrics expert and if I knew what it was I'd, er, know what it was. So please do try any ideas of your own!

 

[George Elliott]

Paul, my guess is the ignition switch on the back of the Ignition barrel. (On the basis you have a good battery) As you know there are number of key stages bringing power on to various areas, and it sounds like the Main Headlight contact and Ignition On are high resistance, the Main Beam flash current highlighted this, and the Off/On at the end of the journey did too. When it cooled down later it was ok, and if the worn contact was better that time the heat build up of high resistance would not occur. How many miles...is it an original switch? I changed mine - its one of the best opportunities on a 944 to remove skin from ones hands, sharp edges every where.[&:] Just a thought Hope you find it without trailering George 944t

 

[Lowtimer]

I carry a spare DME relay - the updated one with (I think) the 993 part number - and hadn't thought about trying the swap-out to see if that helps. When I get my car out again from its current dehumidified comfort, if the problem comes back I'll perhaps try that and the ignition switch. George, can I assume that the ignition switch comes apart from the lock barrel so that one can continue to use the original key? I've never done an ignition switch on anything before.

 

[bmnelsc]

ORIGINAL: Lowtimer ... George, can I assume that the ignition switch comes apart from the lock barrel so that one can continue to use the original key? I've never done an ignition switch on anything before.

The (key) cylinder can be removed from the old switch and placed in the new one (at least that is the normal case). This is how locks get matched to existing keys - by removing the lock barrel and changing the brass plungers to line up with the desired key profile. Removal is usually done by depressing a blocking pin and rotating the key cylinder counter clockwise (with the key inserted) until it stops and then withdraw the whole cylinder from the switch. I must confess I haven't done a Porsche but worked this way on other vehicles.

 

[Paul190H]

Thanks guys for your responses, sorry for slow response my end, telephone line has been down at home for 10 days and counting[][] Bt probably the worst communication company in the world [] Car has done 165K miles so it could be the switch. Frank, thanks for the advice, I was thinking a relay of some sorts. Not sure if the relay is original but at that cost, probably a good place to start. Will keep you posted.