vanagon alternator wiring harness upgrade

If you have an auxiliary battery in your Vanagon you may want to beef up your alternator wiring harness. GoWesty sells an alternator wiring harness upgrade kit for $40 that will upgrade the entire harness. It consists of the wire that goes from the alternator to the starter, the field wire, and the wire that goes to the fuel injectors. It’s a nice upgrade, but we decided to do a partial upgrade ourselves for kicks. Click through to see how we did it.

The stock wire between the alternator and the starter is 8 gauge and GoWesty says a bottleneck can occur there if you have the auxiliary battery kit. GoWesty’s kit includes a 6 gauge wire that goes from the alternator to the starter, a nice improvement. We decided to place a very beefy 4 gauge wire between the alternator and the starter and the results are amazing.

alternator wiring upgrade

We bought our own wire, crimped it, and covered it with heat shrink.

After installing the new wire, the van starts much easier and we get more voltage for charging the batteries. Whether you make your own wire or buy GoWesty’s kit, you should definitely do this upgrade.


It’s a little hard to see in this blurry photo but the beefy red wire is the new 4 gauger that goes to the starter. If you have installed the GoWesty kit, let me know how it went in the comments.

  • fred

    walmart had a 24 inch 4 gauge battery cable for $5 – i added this to the existing harness on top of the stock 8 gauge – fit perfectly.

  • jwallis

    It doesn’t make any sense to me that a wire from altstarter would help you charge your batteries, as claimed on GW’s site. I guess the van starts easier because the current flow goes battaltstarter ?

  • dbeierl

    The van starts easier because they cleaned up the contact from battery cable to starter post — or because the battery is charged better. The charging wire goes to the starter only because there’s a big fat cable to the battery already present there. Starting current never flows through the alternator wire.

  • 65Tops

    Its also a good idea to add a thicker gauge wire from your start battery directly to your isolator instead of relying on the stock 12 ga wire that goes through your refrigerator/switching relay.

Copyright © 2007 - 2017 by

Volkswagen Vanagon, Westfalia, Westy, Transporter, , Doka, T25, T3, Camper, Syncro, Microbus, Caravelle, Custom Vanagon Modifications, Automotive Parts