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03 996 - Keeps killing batteries overnight...

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15 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCH03 996 - Keeps killing batteries overnight...

Leading reported evidence

Use ebay

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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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.

Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

I used eBay to find the switch and actually bought an extra for next time.

03 996 - Keeps killing batteries overnight...
Frequently discussed work

Disconnect negative terminal

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

With the car off, disconnect the negative terminal from the battery and connect a volt meter between the battery and the cable to read the drain.

03 996 - Keeps killing batteries overnight...
Read full discussion summary

Leading evidence: 'Use ebay' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Disconnect negative terminal' (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.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

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1 matching discussions · 15 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Disconnect negative terminal

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

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.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

With the car off, disconnect the negative terminal from the battery and connect a volt meter between the battery and the cable to read the drain.

03 996 - Keeps killing batteries overnight...

Test the hood light would need

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

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.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Interior lights should be preferrably off during this test, the hood light would need to be allowed for, if on.

03 996 - Keeps killing batteries overnight...
Frequently discussed actions (3)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Disconnect negative terminal

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

With the car off, disconnect the negative terminal from the battery and connect a volt meter between the battery and the cable to read the drain.

03 996 - Keeps killing batteries overnight...

Test the hood light would need

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Interior lights should be preferrably off during this test, the hood light would need to be allowed for, if on.

03 996 - Keeps killing batteries overnight...

Use ebay

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

I used eBay to find the switch and actually bought an extra for next time.

03 996 - Keeps killing batteries overnight...
Coverage and how to read this overview

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.

15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

1 acknowledgements have no verified action link; they do not establish a repair result.

Outcome without a verified action link

But it absolutely solved the problem.

No unique explicit quoted action; no causal link assigned

Generation: 20261027T035758Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

my 03 996 cabriolet keeps killing brand new batteries overnight. Anyone have any idea where to start looking? Thanks!

POST 2Original post

Do a search on here or on Renntech. I seem to recall something about a faulty ignition switch being one of the causes of the drain.

POST 3 / ORIGINAL POSTEROriginal post

cool, will check it out...thanks!

POST 4Original post

If you leave the key in the ignition it might drain the battery overnight...for me it was more like over the weekend.

POST 5Original post

One thing I do to narrow the source down is pull fuses and look for the biggest spark.

POST 6Original post

I spent 12 months trying to find a similar problem with my 99 Tip/Cab. The stealer charged me $900 over four visits....they could not solve the issue. I just kept my car on a charger while in the garage.

POST 7Original post

With the car off, disconnect the negative terminal from the battery and connect a volt meter between the battery and the cable to read the drain. You will probably need a mili-meter for small voltages. Then start pulling fuses one by one to see what is drawing the most. Very tedious but necessary.

POST 8Original post

Bullet, Look here for the DIY for ignition switch replacement. I think that mine had gone out for a while predating a battery replacement. The good news is that about $20 and 40 min later, it's fixed. I used eBay to find the switch and actually bought an extra for next time. http://www.renntech.org/forums/index...ch+replacement Good luck! Tonger

POST 9Original post

If you are flattening brand new batteries overnight then you are pulling a huge current (more than 1 Amp). Assuming a 80 Amp Hour battery, that is about 2 or 3 Amps over 24 hours. As suggested, I would connect a multimeter in line with the negative terminal (remove negative terminal and connect through multimeter, set to high current reading initially), put ignition position in the state that causes the issue, possibly key out. As suggested, pull fuses one at a time until the current drops well below those observed during fault stage. Suspect the steady state current should be well below 1 Amp or 12 Watts. If this does not reveal culprit, then I would look for non fused items, such as Ignition Swtch. Interior lights should be preferrably off during this test, the hood light would need to be allowed for, if on.

POST 10Original post

I went through this - turns out the WereWife had inadvertently switched on the passenger side Recaro's fan as she exited the car. Two batteries later, I heard the hum.

POST 11Original post

porschedog better to feed power from the ignition switched supply for the Recaro's relay?

POST 12Original post

Quotes source post: 5698381

Takes me several months to kill 'em.

POST 13Original post

A few years ago I had the same problem with a Sterling (Rover, Accura thingy). I started at Sears (as they were always giving me replacement batteries (in warranty!) and finally asked them where to go to chase this down. They directed me to an automotive garage that specialized in electrical issues. Took them about 1-2 hours to chase it down. They ultimately removed a fuse that was causing the problem. What it controlled was beyond them and me. But it absolutely solved the problem. As seen above, you need to be systematic by looking for which circuit is pulling the most amps. Sometimes with small amp losses (perhaps a full battery drain down in 3-4 days) it's hard to chase with something simple like a multimeter,--but with the sort of drain you are getting (24 hours to dead) it should stick right out. Find a specialist. RARELY will a Porsche dealership be effective here. You need an electrical specialist. Lucas,--Prince of Darkness!

POST 14Original post

when I bought my 03 C4S it had an old Napa battery. the car sat for about 2 weeks after I got it. Then I took a long drive on a Sunday. On the following Monday the battery had drained out, and the alternator was shot and had to be replaced as well. No problems since then, but I do put the car on a CTEK/Porsche charger on weekends, or if I'm not going to be driving for a week or more.

POST 15 / ORIGINAL POSTEROriginal post

Found that pulling the fuse for the top/windows solves the problem. Now I need to figure out what exactly is wrong in those areas.

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