I just got a good deal on a factory hitch for my '91 245SE. It came with all the hardware and the wiring pigtail, but not a receiver. I've never had a car with a hitch, so I've what might be dumb questions.

-Where in the car do I find the wiring for the pigtail to tie into?

-It accepts a two inch receiver, but I don't know what kind of drop/rise/length I need, nor what size ball to get. Is there a correct answer based on the car, or does it depend more on the trailer? I'm looking at this one because it seems like a good price, what do you guys think? http://www.amazon.com/gp/product/B001EOV492/ref=noref?ie=UTF8&s=automotive&psc=1

Thanks!

I've had three 240 wagons with trailer hitches. I bought a trailer wiring converter from U-Haul, which allows the trailer brake light to also act as a turn signal, the standard way trailers are wired. I made most of the connections within the left wheelwell. A good ground is important. The four-wire flat socket for the trailer wiring plug can be mounted under the aluminum rear bumper, or on the hitch bar, by drilling a custom hole. Perhaps your hitch bar has a place to attach the connector.

The ball size depends on the size of the trailer tongue socket. Your Volvo can take a 1-7/8" or a 2" ball, but doesn't have the tow capacity for a larger size (more trailer weight). The most versatile receiver is one that has adjustable height, but is a bit bulky. Mine is by Masterlock, and I think I got it at Walmart several years ago. You can also get a straight receiver insert, or one a bit more flexible that has a two inch drop (or rise if upside down) at the end. Buy two balls, one 1-7/8" and one 2", as well as a long wrench made specifically for hitch ball nuts. It all can be kept (along with your fire extinguisher, tools and a first aid kit) in wheel well storage or under the rear deck if you don't have a third seat.

I had extra strong rear leaf springs (200 lb extra capacity) installed in one wagon, but the regular springs are probably okay for a light trailer. Be nice to your transmission and disable overdrive when going up hills. Be careful braking, especially on curves, as the trailer can push your rear sideways some. If you need to brake hard, drive straight while doing that, then follow the curve. Load the trailer so there is weight on the trailer tongue.

The 240's are tough enough to be very versatile.

I made up a system of relays to tie the trailer pigtail into the car so the extra current flow would not exceed the limitations of the car wiring, or trigger the bulb failure sensor. The car's tail/brake/turn wires are available at the left rear corner of the trunk. Others familiar with your model year can advise as to which wire colours mean what.

For the cost and effort I probably should have gone to a hitch shop and bought an adapter. You will need some sort of adapter to connect the Volvo setup with its separate brake/turn lamps to the trailer, which nearly always uses the brake bulbs as turn signals.

General info here: http://www.accessconnect.com/trailer_wiring_diagram.htm

And a hitch shop can advise you on the right receiver choice.
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Bob: son's XC70, dtr's '94-940, my 81GL, 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.