bojackson Posted September 8, 2023 Report Share Posted September 8, 2023 In the last few days my 2016 VW Tiguan will not start after sitting overnight or for an extended period. Jumps and restarts easily. Had the battery checked twice and the alternator and both checked out fine. Any suggestions on someone locally who could maybe diagnose what is causing the problem short of making a trip to the VW dealer in Guadalajara? Quote Link to comment Share on other sites More sharing options...
Ferret Posted September 8, 2023 Report Share Posted September 8, 2023 I just had the same problem on a 2020 Mobi Fiat. Escalera (opposite S&S Auto) fixed it although I was without my car for a total of two weeks. Had to get an electronics guy out from Guadalajara and replace a faulty "chip" panel. Then it wouldn't start again and I had them check for phantom draw but was without the car for another week. Don't know what they did but it's working fine now. Knock on wood. It wasn't cheap either because it required new keys for the doors. One key was 4,000 pesos but one with a fob would have been 8,000 pesos and I just gagged on the price. Hope your problem isn't as bad as mine was but I trust Juan Carlos at Escalera. FYI, now, I always turn off the air conditioner when I turn off the car... just to be safe. So far, so good and nearly two weeks without a problem. Damn new fangled contraptions that cars are nowadays. Just to bring that point home... Juan Carlos drives a VW bug. Quote Link to comment Share on other sites More sharing options...
Stream Posted September 8, 2023 Report Share Posted September 8, 2023 Electronics can fool you. First thought is a bad cell. Once running the the charging and other ceells can cover for the bad cell but I'd call it a leaky cell that drains the other cells down while sitting idle. There's normally 6 cells with 2 volts each. Alternator charges to 15volts so after turning off one bad cell gives you 13 volts good for starting but after sitting idle the drain gets to it. Then there's the alternator diodes. If it's an alternator not generator the alternator makes AC and diodes are supposed to be turning the alternating current into DC. But of the diodes start flaking out it can be off and on going back and forth from DC to AC to DC and on and on. A digital multimeter should be able to spot that problem seeing the positive and negative emblem of the meter swap back and forth once in awhile. Sears one time after a neww battery and it happened again that the battery went dead I told them it's the alternator diodes. So they wheel out the big tester cart testing everything and through another battery in hehehe. 3rd time they changed the alternator. A regulat needle type multimeter won't spot the negative and positive emblem switching around. Quote Link to comment Share on other sites More sharing options...
TelsZ4 Posted September 8, 2023 Report Share Posted September 8, 2023 I think someone’s trying to baffle you with bull S&$@ there. If you took it to Autozone they would do a load test on your battery and give you a print out showing you the condition of the battery.. if it was me I would see if I could find another battery to use for a few days to see if the problem still happens.. Or take the negative wire off the battery every night. and it still happens. If the alternator was intermittently bad the battery would die when you were driving around not always after the car sits for a few hours. If the battery is good What you probably have is a partial short to ground somewhere.. if you’re at all handy and have a multi meter you can check for a short to ground. This is a very simple explanation. Disconnect the negative wire on the battery, select amps on the multi meter, you need to move the meter lead’s around for amps. connect the multi meter in series with the battery which means black lead on the negative terminal of the battery, the red lead on the wire you disconnected from them battery. Make sure everything is turned off, doors closed you should only be drawing a few milii amps out of the battery., anymore and you have something going to ground, so now start pulling fuses until the draw from the battery drops to mill amps. That will tell you which circuit it’s on so now you would need a circuit diagram to figure out the wiring.for that fuse..These kinds of grounds can be tricky to find because they aren’t big enough to blow the fuse… Or just take it to a garage.. 1 Quote Link to comment Share on other sites More sharing options...
Brian Dalziel Posted September 8, 2023 Report Share Posted September 8, 2023 When I had this problem with my Volkswagen Crossfox I discovered the battery was being drained by a small interior light that was switched on in the rear luggage storage area. That area was hidden under a cargo security cover, so I could never see that the light was on, even when it was dark outside. Quote Link to comment Share on other sites More sharing options...
Ferret Posted September 8, 2023 Report Share Posted September 8, 2023 This is what I printed off and gave to Juan Carlos (I used the translator to Spanish with Windows 10) the second time it happened. Interesting read... Can An Alternator Drain a Battery? - AutoZone Quote Link to comment Share on other sites More sharing options...
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