Turn key and everything instantly goes completely dead. - 986 Forum - The Community for Porsche Boxster & Cayman Owners

I'm really freaking out here. My 2003 Boxster just turned 20 this year and I decided as a birthday present I would give her a beautiful shine. I watched all sorts of videos, bought all the things, washed, rinsed, claybar, wash, rinse, dry, polish (love my new Milwaulkee dual action polisher), and waxed her up to a beautiful shine, looks brand new. So happy. Everything is right with the world and life is gift. During this whole process I obviously had to drive in and out of the garage several times, including a trip to the UPS store to return the cordless angle grinder Amazon sent me instead of the cordless polisher I had ordered. After polishing and waxing she looked so great I wanted to back her out into the driveway to blind myself by the sun reflecting off her mirror like surface. It was glorious, and when my vision returned I decided to take a celebratory lap through town before I pulled her back into the garage. I put on my sunglasses, buckle up for safety, stick in the key, watch the little oil thingy do its little dance, all systems go I turn the key. Instead of the sultry vroom I was expecting, I was greeted with instant silence. I mean instant, there was no rerrr...rerrr....rerrr.. from the starter, the dash instantly went black, and absolutely nothing worked. It was very mush like plugging a table saw and air compressor into the same outlet, so my first thought is a fuse, but does a car have a master fuse that shuts down the entire show? That one is above my pay grade, so first I decide to check the battery, except of course I can't because I can't release the hood latch with no power. I've run into this issue before, so I was prepared. I keep one of those little lithium-ion jump starters in the glove box for just such an occasion. I hooked it up to the connector in the fuse box, popped the hood, checked the battery and it was 12.47 volts just as I expected it would be. You see, the only problem I have ever had with my Boxster is the battery would die if it sat very long at all, even a week or two. I would charge it all the way up, drive around a bit, everything would seem fine. Turns out, my alternator was bad and it was running entirely off the battery, so charging it up to full was masking the issue. After I figured out the problem I bought a genuine AC Delco replacement alternator about 6 months ago and have never had another problem since. So it's gotta be a fuse, right? Battery is good and it died instantly like flipping a switch, that's a fuse. It's odd that everything went dead all at once, but it seems logical to me that there might be a main fuse like the main breaker in a breaker box. I did some searching on the internet, and didn't find any mention of a main fuse, so I decide the next logical step is to just pull each fuse one at a time and look for one that is blown. I go back out to the car and it seems to be working again? When I turned the key to the on position the dash lights up and the vent blower is working, but before I try to start it I remember something I'd just read about the immobilizer. When I bought this car it only came with one key, but in the glove box was a brand new key and a brand new key fob ordered directly from Porsche and still in the packaging addressed to the previous owner (I assume, I bought it from a dealership). The car was in excellent condition and the Mercedes dealer I bought it from said to simply take the key down to the Porsche dealership and they'd activate it for me. The Porsche dealership was more than happy to activate the key, for like a hundred and fifty bucks, but since the key and fob still had the invoice in the package, I didn't mind the activation fee so much considering the previous owner spent almost 500 bucks on the new key! I always wondered why the dude went to the trouble of buying a new, rather expensive key for a car he was about to trade in. I'm not a rich guy, so I don't know how rich guys think, I figured maybe the expense was nothing to him and he just wanted to make sure it was complete, the car really was in immaculate condition, so I know he took very good care of it. But then I thought, what if the old key fob was intermittently acting up? That would make total sense! If the car was intermittently not starting, and he took it to the dealer and they were like, it's the key fob, he might have ordered a new one, but decided to sell the car before he activated it. I normally use the new key, but I keep the old key in the garage in case I want to back it out into the driveway, like to wash it or something. Today I was using the old key, so before I attempted to start it again with the old key I went into the house to get the new key. I stick the new key in, turn it to the on position, everything seems fine, turn it to start and... everything instantly goes dead. WHY DIDN'T I PUT THE TOP UP WHEN IT WAS STILL WORKING!!!??? Now it seems dead dead. Even after waiting a much longer time than I did last time, it's still not working with either key. I've searched and searched, but can't find a similar circumstance on the internet. I'm in a real pickle here. My prized possession is sitting in the driveway with the top down. While I've been typing this I've been waiting to go give it one last try, let's see what happens... and... nothing. I'm going to start pulling and testing each fuse individually and will report back.

It`s probably either the battery terminal or the main power line terminal behind the seat, which sits under a black plastic cover under the engine compartment lid. Probably corroded. I would check these first. Fuses protect individual components, so it won`t be that.

Quotes source post: 652620

Could be a dying battery -- and/or corroded connections on the power cables. As mentioned the power cable goes from the battery -- to a post on top of the engine -- where it then goes to the engine and starter. Put the battery on a charger, maybe one with a jump start capability -- but don't try and start it -- just use it to put the top up. I like to use the newer Li-Ion jump packs to start it when the battery is low. And if this persists -- replace the battery. Mike

Embarrassingly I figured out my problem right away, and although I tried to immediately update this post, I guess the forum mods manually approve posts here? I find that most bizarre, like a chatroom on a dial up BBS from the 80s or something. I even checked back the next day and the post still hadn't been posted. At any rate, I decided to start pulling fuses one by one looking for a blown fuse and figured that perhaps it wouldn't be a terrible idea to disconnect the battery terminal, because you just never know, inrush current can do strange and terrible things. The second I touched the battery terminal I heard a click. There was no corrosion on the terminal what so ever, and giving it a little wiggle was met with no movement at all. Yet when I gave it a good tug it moved at least 45 degrees! After torquing the retaining bolt to proper German specifications, guten tight, the problem was resolved.

Quotes source post: 652894

Glad you figured it out