Quite a long story, but quite entertaining if you like fault finding or have ever spent a long time searching for a fault. This is about my Jetta Gti which is a sort of spare car, bought cheaply. The battery went flat whilst the car was parked up. So I bought a new battery at the motor factors. Fitted it. One week later, after the car had been left in the same place, battery was flat again. I wondered if I'd left the interior light on. Which I had. So I turned that off, used some jump leads and drove the car for a bit to charge the battery. Another week later and the battery was flat again. So I had to face up to it and fix it. Well, late this afternoon I finally got stuck in with the multimeter. Bear in mind that I don't have the Haynes manual for the car, nor had I ever followed the wires in a Golf/Jetta. I was just going to work by following wires and working it out as I went along. So I disconnected the flat battery and put the multimeter across the + and - wires and measured the resistance. It was infinite. Seems a bit odd when there's a current drain. This took a while to solve. It was a brand new multimeter and I hadn't plugged the leads in all the way. LOL. With that sorted it was showing quite a low resistance. I unplugged fuses one by one, each time checking the resistance. Fuse 3 made a difference. So did 7. I looked up what these were: 3 was interior light/radio/cigarette light. 7 was rear lights+sidelights. So I took the centre console out (first time) and disconnected the cigarette lighter. Made no difference. I had my suspicions that the alarm remnants were not helping. Under the bonnet I had found a disconnected alarm wire. So I decided to remove all of the alarm. This involved taking all the lower dash off on both sides. I found a whole load of redundant wires that looked like they went to a missing alarm unit. They'd tapped into the lighting cirucuits with Scotch blocks. Always a bad sign. I completey removed the alarm system. It was good, I slowly found out what the various wires were. Two went to "microphones" in the car, one odd wire went to the flashing LED etc. I also had a fiddle in the boot. I found a load of pipes which confused me for a bit. Then I realised it was a central locking system. Doesn't work on the car though. After all of this then the fault with fuse 7 had gone. So I was just down to the fault on fuse 3 circuit. Interior light. By turning the switch on this I got different resistance values across the battery terminals. Sounded promising. So I removed the light and had a look. Nothing very exciting. Off was clearly off. I followed the wires down the A pillar and saw that there were various connectors near the fuse box. I tried disconnecting these in turn but nothing made any difference. By this time I decided to just remove fuse 3 and put the car back together and sort the problem another day. So I put it back together. At 8pm I was up for having a closer look at the cause of the problem. So it was headtorch on and back into the car. I removed the lower dash on the driver's side and had a hood look at everything. By lying upside down in the footwell I could follow the wires. Loads of minor mysterys were solved. The vaccumpipe for the trip computer was spotted, along with a massive multi connector. By wiggling various wires I managed to work out where most of them went. I tried unplugging the multi connector but that made no difference to the resistance value. Next I focussed on the fuse box. I hoped I could follow the wires from fuse 3 but that wasn't possible. So I opted for unplugging the fuse box connectors one at a time. Red one, Blue one, White one, Blue one. Nothing nothing nothing nothing. Black one then? Yes. Wires were followed and I found that they sort of disappeared into the wheel well. I worked out that they went under the carpet and then to the back of the car. Took a look in the back of the car. Rear lights. OK, removed the rear light clusters and unplugged them. No difference. This confused me a bit. So I took another look. Then I noticed that more wires went in by the fuse box than came out in the back. More carpet lifting. Aha, wires came out at the back of the boot. Went to fuel pump and another lot went to boot light. Very suspicious that. Boot light. Classic current drain problem. A bit of time unpicking all the wires for the boot light and I understood how it worked. Hmm, wait a minute, boot is open. Maybe having the boot open all of the time during the testing would be relvevant. Sure enough, if I unplugged the boot light problem went away. I removed the boot switch and cleaned it up. Boot light switch was the cause of the problem. If I disconnected it then problem was solved. Now I know, I could have removed the bulb from the boot and that would have fixed the problem. But I was feeling curious. In the end I found that I could close the boot but the light would stay on. After various fiddles with the bump stops etc I just could not get the boot light to go off. Then I looked in the box of bits and found some ripped up plastic that was the trim that fits round the boot opening. I took a closer look. Aha. I saw the moulded in lump for the switch to press against. So fitted the plastic trim back and the problem was solved. I was laughing by now. So, about 3.5 hours hard work and trial and error and the cause had just been me ripping a piece of trim out weeks ago. Classic.
Great story that! Some useful tips on fault finding there too. Marvellous .. d'ya fancy finding the short that keeps blowing the fuse on my dashboard lights every time I turn the lights on?
lol i know this very piece of shocking platic myself i still need to know if i can get a new one from vw cause mine has had it! i got a new boot switch of a golf reacently that worked a treat too!
