VW Electrics main cables

Introduction - Good Connections

(Under construction)

Intro by Covkid:

Good connections and good cable are essential for effective charging and starting. However, after 30 years work, the main heavy-guage cables that go from alternator to starter and battery can be subject to deterioration. You need at least 4 metres of new cable do this job - suggested types at the end.

The thickest cable by far is the one between the battery and starter and if you drive a T25 with your main battery behind the drivers seat, you'll realise that its quite a distance between the two. The alternator cable isn't quite as chunky but for this upgrade I replaced both of these cables with the same 25mm fine strand cable. Its just about bendable at that thickness.

Cable corrosion

The photo below shows the terrible (although not untypical) state of a cable at the rear of an alternator. Most alternator connections actually terminate in a plug rather than like this and therefore the state of them can easily be missed. The copper within either starter or alternator cable can become brittle and corroded, no matter how far you cut back, and potentially create resistance - reducing the alternator's ability to charge and the starter's ability to turn the engine over.

The vehicle is a 1.9DG and wiring layouts do vary.

Generally, when things have become this bad though, the only thing you can do is replace the cables completely and solder new connectors as required. You can crimp (if you have access to oversized crimps) but soldering makes for a more reliable connection and helps seal the cable.

This particular engine uses a golf alternator and only has a single nut which holds the main cable. I removed the old corroded cable which had been twisted around the post and clamped between two washers (not by me!!) and replaced it with new, thicker cable, and soldered ring connector on the end (see photos below).

The vehicle is a 1.9DG and wiring layouts do vary.