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C

cybermonkey

Hi forum,

This is my first post so i'm not even sure if i'm in the right section for this...

Anyway i've got an intermittent electrical problem with my 8 year old VW Golf. It started about a month ago, I went to start the car and nothing (it was parked for no more than 6 hours), the battery was dead. I called the RAC and they jumped the car no problem, they tested the battery and said it was fine. The same thing happened the next day so I bought a new battery anyway, 3rd day and another flat battery. And then the following week everything was fine with it.

The problem came back again, I went to start the ignition and the alarm starts going off, and i'm getting strange clicking noises from the wiring loom directly under the steering wheel (immobiliser?), I guess the alarm freaked out because it wasn't getting enough power and me trying to start the car triggered it...

So now whenever the car decides not to work and I jump start it or swap batteries, it shows the warning lights for ABS and emissions and the drive is terrible - it's either over or under revving and when it's under-revving it tends to cut the engine out at the lights. I can start it again but it's not an ideal situation to be in!

I've physically checked the cables I can get to, the connections and housings, and although they look a bit dated they all seem sound with no breaks or loose cables. I checked all the fuses with my multimeter for continuity and they all check out fine. When the car was behaving itself I checked the battery voltage with the ignition off (12.5V), and with engine idling (14.2V), so the alternator seems to be ok. When the car is not behaving the voltage drops like stone, and i've checked this immediately after several journeys, I switch off the ignition, get the meter on the battery and the voltage drops down to about 9V. However when the car has been sat there with the engine off for about 10 minutes the voltage starts to go up to just over 12V!! How is this possible with the engine off and no alternator recharging the battery?

The other thing I done when the car was misbehaving was to hook up the meter in series with the battery and circuit, switched to Amp setting and saw it was drawing 3.4Amps. The clock uses 10mA but everything else was switched off. I saw a drop of 42mA after a few minutes but assumed that was the door lights going off. I then took out each fuse under the steering wheel one by one, expecting to see the current dipping at some point, but nothing. Despite me pulling each fuse out the current never dipped below 3A, how is this possible? Should I be pulling the fuses mounted in the compartment above the battery as well?

The next step is to test voltage drop across each circuit all the way to the load, but i'm no mechanic and wouldn't know which part I was testing. The RAC have checked the car twice now and each time they can't find a fault, so I don't really want to get an auto electrician out unless I really have to. And at the moment it's looking that was as this is a real head scratcher.

Has anyone else experienced similar problems with their car? Any suggestions what I do next? Sorry for the long winded description but I hope someone can help, this is driving me nuts :confused:
 
This is an electricians forum matey think your get a better answer if you ask on a car forum. Not being rude but this is electrical installation etc. Cheers
 

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