Voltage drop issue

[adyRE]

Hi,

Had on going issues with my battery going dead / not enough volts/amps to start. Been doing some testing today and found that I'm getting 14.6vdc off the back of the alternator but only 13.4vdc at the jump start postitive terminal in the engine bay and the battery too. Interestingly I found that when I disconnect the cable from the alternator and wire in temporary cable from alternator to positive terminal block in engine bay I get 14.6vdc. So that cable from the alternator to the starter is causing a voltage drop. Now that I've removed it from the circuit and left it taped up I am able to charge my battery at the correct voltage. Does any one have any idea what could be causing this volt drop? And has anyone had this before.

 

[desertstorm]

Looking at the wiring of my 2008 3.0 TDI , I assume yours is probably similar the alternator connects to the starter that then connects onto the fuse box/ connection box where the jump start point is. There is a poor connection somewhere possibly on the starter motor where the two cables are connected together.

 

[adyRE]

Thanks for that wiring diagram. Yep looks like mine is exactly the same. I'm going to leave the temporary cable in for now and get the wiring looked at between the alternator and the starter. The starter is a nightmare to get to so I'm in no massive rush to start taking the whole front end off haha