YOUR RESEARCHHeated rear window defroster turning on at random
1 matching discussions were examined; no attributable action/outcome evidence was detected. No consensus or repair conclusion is claimed.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Read captured repliesInsufficient extracted evidence does not mean there is no answer in the original discussions.
1 matching discussions · 5 captured posts examined · 0 partial discussions
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
5 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T042512Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
My C4S cab has developed a rather strange issue. The defroster seems to turn on at random. The switch seems fine, when it happens I can just switch it back off and I can switch it on just fine. First I was thinking to first try swapping the relay but thought I’d post first in case there’s any usual suspects for this sort of issue, I’ve not had much luck searching so far.
On the basis of zero knowledge. Is your external temp sensor working/plugged in? I don't know if the 996 employs the logic path, but a lot of cars automatically enable the screen heater below say 5C. So if your external sensor is broken and reporting -20, it could come automatically.
Mine does this. On mine, the wire at the rear nearside hard top mount hole, has come away at the solder joint.
Mine does it when the roof is down sometimes.. It went in today to be looking into.. I was thinking as YPVS has said that it was a bad connection around one of those mounting holes
Thanks for the replies, no luck with the above ideas but did find a pointer. The light comes on when the battery voltage has a momentary drop. Like when you put the windows up when they hit the stop point, there’s a momentary voltage drop on on battery guage, this is when the defroster comes on, that makes me think perhaps a bad or low battery that shouldn’t be dropping out like that so easily, it is a 100Ah after all. I’ll put it on the trickle overnight a report back
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