How To: Towing Wiring Harness for MkIV VW Golf, Jetta & Jetta Wagon

US Friendly, VW Plug-and-Play

Using passenger vehicles to tow is commonplace in Europe, and thus most Volkswagen vehicles are especially adept at pulling an extra load.  Bosal, a well known European high manufacturer, makes the OEM hitches for VW.  These hitches, along with those made by Westphalia, are considered the best in the world.  Their no-drill, bolt-on-frame design gives most VW passenger vehicles towing capacity over 3,000 lbs. The Bosal Hitch for MkVI Jetta and Golf is available from our partner, IDParts.com.

The second challenge is wiring.  Most VW models to date use a European style wiring for the rear tail lights where the blinker, brake and running light are on separate circuits.  US trailers, however, use an arrangement that puts all those things into one bulb.  Hooking your Volkswagen to a US trailer requires an adapter to switch from the EU style circuit to the US style circuit.

Luckily for us many VW models include open plugs on the backside of the tail light specifically for trailer wiring.  This article will show you the parts you need to make an easy-to-find wiring adapter work with the OEM trailer wiring connections on your A4 platform VW, otherwise known as the MkIV Golf and Jetta…

For the purposes of this article we will be using a U-HAUL wiring harness adapter, model number XXXX, available for $16.95 as of this writing.  Similar products are available from other manufacturers like Modulite.

You will also need 3 OEM VW connectors, depending on model

Look at the chart below to see which connectors your vehicle needs:

The part number for the respective connectors are:

• 3-Pin 1J0 972 924
• 2-Pin 1J0 972 923 * (these connectors have tabs that need to be filed down to work)
• 1-Pin 191 972 701

And finally you will need 4 VW terminal connectors, available on two repair wires (Qty (2) VW part# 000 979 1

Unwrap your purchased adapter harness and line up all the wires. You’ll find that you have 5 wires total (6 if you have a 12V powered adapter), one each for left turn, right turn, brake, running lights and a ground wire. On the U-HAUL model ‘XXXX’ adapter , 4 of them should be grouped together and one, the right-side-turn-signal, will be separate.

This installation is done on a Jetta Wagon that has been converted to European-Style Tail Lights, but its the same for the Golf and the Jetta Sedan.  The North-American Jetta Wagon taillights, however, use a different wiring scheme which we’ll put at the bottom of this post.

For this installation the three pin connector will take the left turn, tail light and ground wire.

In Order - Left Turn Yellow, Ground White, Tail Brown

These will fit into one of the 3-pin connectors, set the connector with the two alignment fins pointing up and insert, left to right, as follows: Ground – Left Turn – Tail.

Golf IV Towing Harness Pin Layout

The last wire for that side is the brake light, use the 1-pin connector for that.

Brake Lights All on Their Own

Finally, use remaining long wire (right side turn) and insert that into the last three-pin connector, middle slot.

Golf IV Towing Harness - Right Turn Signal

Finally, hop into your hatch, remove the left side compartment panel cover.

Left Side Panel Cover Removed, The Blue Bag is the utility kit that comes with every Bosal

In this photo the U-HAUL harness is double-side-taped to the back of the styrofoam insert (where the 6-disk CD changer would go).

U-HAUL Harness Attached Securely

The only thing left is to plug in the connectors when you are ready to tow. They only fit into one location each, so you can’t make a mistake. I don’t have the harness plugged in when I’m not using it, so I have the connectors and wires nearly wrapped up.

Towing Harness Wires Wrapped Up

Thats all there is to it! Feel free to substitute the U-HAUL kit from one from Modulite or similar, as long as its the same adapter style it should work fine. Some kits use the 12V socket for power, which may be a good idea if your trailer has a lot of lighting.

Special thanks to Chris R. for feedback and suggestions!