Installing Trailer Wiring and Adding a 6-Way Adapter to a 1989 Volvo 240 Series Wagon  

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Expert Reply:

You are correct. We do recommend the Upgraded Circuit Protected Taillight Converter Hardwire Kit, # 119178KIT, for your 1989 Volvo 240 Series Wagon. Vehicle specific installation instructions are not available due to the fact that this harness fits many vehicles. But there are general instructions which I will outline below.

First, you will need access to the wiring behind each tail light. Starting on the left (driver) side, you will need to find a place to mount the converter box. Then, ground the white wire to a bare metal surface. Next, use the included circuit tester to probe the wires until you find the one that carries a signal in unison with the left turn signal. Attach the yellow wire of the harness to this wire.

You will do the same for the brake light wire (red on the harness) and the running light wire (brown on the harness). Once those connections are made, route the green wire to the right (passenger) side. Find the wire that carries a signal in unison with the right blinker and connect the green wire to it.

The 4-Way will remain stowed in the rear cargo area until needed. You can close the rear hatch on the wires and it will work fine. Just do not let the wires get pinched in the latching mechanism. I have included a link to a video that shows a typical installation. The only tools you should need would be what is needed to gain access to the tail light wiring and a powered screwdriver or drill with a screwdriver bit (for connecting the white ground wire).

Since you need to use an adapter, the Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter, # 37175, would be a good choice. However, this does require routing the 4-Way connector in the 119178 down through the bottom of the cargo area and out to the rear of the vehicle. You will probably need to remove some panels and flooring to get to the metal of the cargo area.

There may or may not be an opening, plug, cap, or grommet that you can use to route the wiring through. If there is, then use it but make sure you seal up any holes with silicone. If there is no existing hole, grommet, plug, or cap, you will have to drill through the bottom of the cargo area, pass the 4-Way through, and seal it up. When drilling, take extra care not to drill into anything on the other side like wiring or a fuel line.

Once the 4-Way is routed to the back of the vehicle, you can connect it to the adapter. The adapter comes with a mounting bracket for a professional appearance. It can attach to the metal frame somewhere on the underneath of the vehicle near the back. You will want to avoid attaching it to the hitch.

The remaining wires on the adapter are for the other 2 functions used by the trailer and there is also a white ground wire that will need to be connected first. The blue wire is for electric brakes and will attach to the blue wire of a brake controller.

The black wire is for 12 volt power and will need to connect to the positive battery terminal via a 40 amp circuit breaker, # PK54540. In order to reach the cab of the vehicle where the brake controller would be and the vehicle battery you will need extra wiring, # 10-2-1, about 20 feet worth.

When routing the wire underneath the vehicle, you will want to avoid areas that may pinch or burn the wires. Use wire ties periodically to attach the wires to an existing wiring harness or the vehicle frame. This is so it is not hanging down while you drive.

For a brake controller, I recommend the Tekonsha P2, # 90885. It is one of our most popular controllers because it is easy to set up and easy to use. I have included a link to the installation details for reference.

expert reply by: Michael H

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