15 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
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YOUR RESEARCHRear screen defogger
Leading reported evidence
Replace operation - it works
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Suggestion · Original poster
New relay fitted and no change for the operation - it works but only for 1 minute, then it turns itself off.
Leading evidence: 'Replace operation - it works' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace operation - it works' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion · Original poster
Ok - changed the relay for a new one but still no change - the rear screen heater only stays on for 1 minute before turning off.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Unsuccessful attempt · Original poster
Ok - changed the relay for a new one but still no change - the rear screen heater only stays on for 1 minute before turning off.
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15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Outcome without a verified action link
New relay fitted and no change for the operation - it works but only for 1 minute, then it turns itself off.
Does anybody know how long this should stay on when selected?
Mine only seems to stay active for about two minutes, then switches itself off - it hardly clears the screen in this time so I end up having to repeatedly turn it on to clear the screen.
I'm thinking that the relay has a timer in it that is faulty?
I believe the later models and the 997 one stays on for 15 minutes.
You may need this Porsche Rear Window Defroster
Control
Relay 99661511700 Its more than likely under the dash by the steering column. There are about 8 behind the ignition switch area. Get your iPhone under and take a photo and see can you see the same part number on one of the relays.
http://www.ebay.com/itm/Porsche-Rear...81257956669%26
But before you go spending, if you can see an identical relay near the one controlling your rear window, then swap it out and try it again. Then you will know for certain.
Not sure but the relay may heat and switch off, then cool and switch on, repeatedly so give it chance to switch back on.
(if that's how it operates). Maybe the heating connection inside the relay is going wrong. Hey only guessing here or thinking out loud.
yes when i noticed mine shut itself off, I was wondering why, all these possibilities ran through my mind, as well as it frying itself and all the little wires in the glass
Thanks for the replies - it stays on for approx. 1 minute then switches off - no sign of it coming back on again by itself but a good thought Hurdi.
guess I'll have to get myself upside down in the footwell and try and swap the relay out !!
More UK class in action .. Thanks to Jay from the Isle of Skye. Hey there may only be one of that type of relay on the car but you could remove it and have it tested at a local parts store. Also I only guessed that it may be in that bank behind the ignition. I have more under the back window sill but I have the cabriolet. Mind you don't do yourself a mischief under that dash board haha.
Defogger relay is on relay panel 1 position 4 and should be the one above the fuse panel.
I'm waiting for a new relay to arrive and will update results when it has been fitted.
Ok - changed the relay for a new one but still no change - the rear screen heater only stays on for 1 minute before turning off.
Any other thoughts or ideas of where to look to solve this issue gratefully received!!
Same issue, short on time so I ordered a new relay. As soon as I get a slot cleared out I will get the car in and replace it. Looked at the schematics and it appears the relay is turned on and off by the switch and that's about it. I will know more when I open up the old one if this doesn't fix this. The relay could have a over current device in them since this one relay powers all the heated mirrors and rear window.
Good thinking Adker - I didn't consider an over current device in the relay.
I will open up my old relay also tomorrow and see if there is anything obvious.
I did find an old TSB that referenced this problem, but it only says that there was a manufacturing issue with one batch of relays and the solution is to change out the relay for a new one!! The sheet is from some time ago so I can't believe that any newly purchased relays would be from the original bad batch.
ok - lost for ideas now so any other thoughts appreciated.
New relay fitted and no change for the operation - it works but only for 1 minute, then it turns itself off. It has to then be switched back on every minute to defog the screen.
I cant see any sign of overcurrent protection in the old relay, but then I am no electronics expert.;
