Cooks Posted March 12, 2019 Report Share Posted March 12, 2019 Well, I guess this is all the joys of a Porsche ownership. Following on from my last thread I had a bad alternator pulley bearing which was making awful noises. Had the alternator fully rebuilt with new regulator. Before this I was having battery drain issues and thought it must have been the alternator failing. Bought a new battery before Christmas too. I am still getting crazy battery drain. Take the battery off and charge it with my trickle charger it is fine. Holds charge once removed from the charger. When connected to the car the battery is dead within a couple of days. Maybe even a day! I don’t use the car during the week. I am going to start on with my multi meter tonight testing for any leaks when key is out. Door locked and let rest for an hour. Will the front boot being up cause a problem? Also, I can hear a constant humming coming from the horn ( sliver dish under plastic on driver side) when the battery is connected. This is before I put the key in the ignition just press the key to silence the alarm once battery connected. Also, the glove box light does not turn off when it is shut? Is this on a time loop. Tested this by putting phone on record and closing the glove box. Car has an aftermarket stereo fitted by the previous owner also! I have read about an earth strap? Does any one have any info on this. Any tips before I get started as this is new territory for me! Thanks, Link to comment Share on other sites More sharing options...
Nobbie Posted March 12, 2019 Report Share Posted March 12, 2019 Sounds like you have plenty of avenues to explore there. Seems weird the glovebox light bring on a time loop, did you say you have tested this and found that it does go off after a while? You could try removing the bulb to eliminate this as an issue. Horn buzzing sounds odd, again any chance of isolating this or putting a meter in series to measure current drain when car 'asleep'' I think the aftermarket stereo fit is worth investigating, maybe they have connected a permanent live rather than a switched live somewhere. Can you turn the stereo on with the ignition off? Not sure the car will properly go to sleep with the bonnet up, could you find the microswitch and tape it in the closed position? Good luck🙂 Link to comment Share on other sites More sharing options...
½cwt Posted March 12, 2019 Report Share Posted March 12, 2019 Aftermarket stereo wiring would be my first target, although if horn seems to have an issue looking for moisture in the electrical system somewhere would be another route to follow up if there's still an issue after checking the stereo. Does the battery hold charge if not connected and check the no load voltage. Last one I had issues with was down to 9.8v... Lead acid batteries don't react well to being discharged too much too often (deep cycle) and it tends to kill them pretty quickly particularly with a bit of cold weather thrown in. Link to comment Share on other sites More sharing options...
Cooks Posted March 12, 2019 Author Report Share Posted March 12, 2019 Battery seems fine when it isn’t connected to the car. I will get my meter out tonight. Interestingly I pulled the fuse from the horn and it was still buzzing but when pressing the horn on the steering wheel. The horn did not sound. Is there anything else in that’s area which could be buzzing? It’s a very slight humming. @Nobbie radio turns on and powers up when the key is not in the ignition. I have pushed the bones latch in manually with a screwdriver allowing me to keep the bonet open. The glove box light is not lit anymore if I lock the car while inside and open the glove box. So assume the micro switch thinks the car Bonnet is closed. but still a humming from that area?!! Link to comment Share on other sites More sharing options...
Cooks Posted March 12, 2019 Author Report Share Posted March 12, 2019 2 hours ago, ½cwt said: Aftermarket stereo wiring would be my first target, although if horn seems to have an issue looking for moisture in the electrical system somewhere would be another route to follow up if there's still an issue after checking the stereo. Does the battery hold charge if not connected and check the no load voltage. Last one I had issues with was down to 9.8v... Lead acid batteries don't react well to being discharged too much too often (deep cycle) and it tends to kill them pretty quickly particularly with a bit of cold weather thrown in. Where would you be looking for moisture ingress. The car has been kept in my garage for the last 10 months and the problem is only pretty recent. 😐😐 Link to comment Share on other sites More sharing options...
DrKW59 Posted March 12, 2019 Report Share Posted March 12, 2019 If you've latched the bonnet (frunk/froot) you're good to go as the car thinks it's secure. Not sure I understand the glovebox light though, seems like a faulty switch?? but that bulb wouldn't drain your battery in a few days. My money is on whatever is humming. I'm afraid I haven't a clue what it could be but you really aught to isolate the horn completely and not just rely on the fuse. I believe there may be two horns which may also double up as the car alarm and I doubt if pulling the horn fuse would silence the alarm. (of course I may be wrong ) As far as water ingress is concerned the major culprits are well documented but first stick your hand under the passenger seat carpet behind the seat. If the foam backing is wet then then there's your issue. Good luck, I feel your pain as I too (still) have an as yet undiagnosed battery drain. Kevin Link to comment Share on other sites More sharing options...
½cwt Posted March 12, 2019 Report Share Posted March 12, 2019 2 hours ago, Cooks said: Where would you be looking for moisture ingress. The car has been kept in my garage for the last 10 months and the problem is only pretty recent. 😐😐 It was just a general point on possible causes, the info about storage wasn't in this posting...😕 Moisture or corrosion as a result of moisture is a common cause of current drain. In you case, not so much maybe. Link to comment Share on other sites More sharing options...
Menoporsche Posted March 12, 2019 Report Share Posted March 12, 2019 Water ingress is one of the most common causes of random electrical problems in these cars - as above, feel under the pax seat carpet. Another common cause is the ignition switch, and rogue Trackers that have been generally but not sufficiently deactivated. But I agree, other than a hand under the carpet I'd be carefully examining that aftermarket stereo. Link to comment Share on other sites More sharing options...
Cooks Posted March 12, 2019 Author Report Share Posted March 12, 2019 Multi meter connected to 10A dc pulling a 0.30 draw. So quite high. Worked through all the fuses D7 - rear spoiler dropped the voltage to 0.01- 0.02 so that’s about right I believe. About 20 mili amps? any ideas why the rear spoiler is having so much draw. Oh and the humming noise was still there even at 0.01! Maybe it is for the alarm or something. Car alternator charging battery a 14.23 which I believe is spot on too. The aftermarket stereo fuse did not drop the mili amps at all. Any ideas about the rear spoiler. Will leave it unplugged until I work out why! Link to comment Share on other sites More sharing options...
Menoporsche Posted March 12, 2019 Report Share Posted March 12, 2019 Check for water in the boot, possibly around lights, someone recently got their rear spoiler control unit wet. A new one on me but apparently it happens. The humming makes me wonder about the badly-disabled Tracker. Link to comment Share on other sites More sharing options...
Cooks Posted March 12, 2019 Author Report Share Posted March 12, 2019 If I disconnect the alarm siren it stops humming. It flashes amber like mad but stops humming. It’s as if the alarm is alway ‘priming’ do you know how to access the spoiler control unit. No wet in the boot either! Link to comment Share on other sites More sharing options...
Boxob Posted March 12, 2019 Report Share Posted March 12, 2019 Is there (or could there have been) water in the bulkhead trough where the battery is located? A blocked front drain will do that. If so maybe damp and corrosion is comprising the electrics in that location. I think that's where the alarm siren is. Link to comment Share on other sites More sharing options...
SiPie Posted March 12, 2019 Report Share Posted March 12, 2019 Probably no help at all to you but the Frunk light staying on was my drain 🙄 Hope you find it soon, a real PITA indeed Link to comment Share on other sites More sharing options...
Cooks Posted March 16, 2019 Author Report Share Posted March 16, 2019 Had a good look around where the battery is there are some leaves and stuff but nothing obvious? Does anyone know how I can check the rear spoiler mechanism / electrical part? Cheers. Link to comment Share on other sites More sharing options...
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