94 940 turbo wagon

Need to add a standard 4 wire flat trailer harness to my 940 wagon to pull a 4x6 enclosed trailer .... my questions are;

1) do I need what I have seen as some special box that goes between the car and trailer lights?

2) Can I just tap into the cars lights at the rear with blade scotch locks? without using any special box?

3) Will any of this cause my bulb failure light to come on the dash?

4) does anyone know the wire colors and best location on the wagon to tap at .. ie, blue with white = stop ... etc ..


Thanks in advance for any help.

 

you need the converter box, they usually come with the lock taps, and yes, you wire it all in back to the taillights, except you need always-on power brought back from the positive terminal thats under the dash on the drivers side near the steering column on a 740/940. put the in-line power fuse that comes with the light controlle kit as close as practical to the positive terminal.

this is like the one I've used...
Tail Light Converter with 4 Wire Flat Extension


when I tapped the wires on my sons 940 wagon (and our 240 sedan before that, and a 850 wagon in the middle somewhere), I just found the wires going to each light socket and traced them. but, see below...

I put the box in the cubby compartment under the floor panel in the left rear, and snaked the wire into the main compartment under the deck... when we towed, we just ran it out the tailgate.

k, 'below'... i have the greenbook for a 1992 740/940 here. all colors are at the light fixture.

left turn - green
right turn - blue-green
left brake light - yellow-red (right one is yellow, but you only need one)
left parking light - red (right one is brown-white, but you only need one)

black is ground back there, but I went ahead and ran the light controller's ground directly off the chassis ground screw thats near the left light.

 

Thank you for your reply, Pierce. I believe WalMart sells Hopkins and I will look this week. I bought a new 4x6 enclosed trailer .. it weighs 650 lbs ... I think total when loaded with what I will be hauling it should weigh about 1000 lbs ... I don't think that will be too much on the old wagon .. it really should be able to just run away with it .... it is the 940 turbo and is geared low ... I'll report back if I have any troubles .. seems pretty basic using that kit .... Thank you again for you time ..

 

a 740 wagon is rated to tow 3500 lbs, but anything over 1500 lbs should have trailer brakes (which means to tow heavier than that you would need a battery on the trailer, electric brakes, a breakaway e-brake safety switch, and some sort of brake controller (can be an inertial controller onboard the trailer, or in the vehicle, which requires a 7 or 9 pin trailer connector).

you -should- derate your vehicles GVWR by the tongue weight of the trailer. a 740/940 wagon has a stock payload cargo limit of 1020 pounds, and normally a trailer should be balanced to put 10% of its total weight on the hitch, so a 1200 lb trailer would put 120 lbs on the hitch ball, and therefore the rear axle.

740/940 wagons are so sturdy, that if you use the wagon overload springs that IPD and FCP sell, you can probably add 200 lbs to the rear axle limits if you have tires with sufficient load factor (say, 91 or 93 instead of 87 or 89) without any problems. DO turn off overdrive when towing anything!!! the OD is NOT strong enough to handle it,and your transmission will last much longer. also if you tow regularly increase the frequency of transmission flushes. turbos and many others have a tranny cooler but not all early 7s did, so any 7/9 that doesn't, you should add one as a cool tranny is a happy tranny, and pulling more weight is hard on the transmission... (get a radiator with the tranny cooler from a turbo from a wrecking yard, and transplant it along with the plumbing).


this is my wife's old 1993 960, back in 2001.... it had nivomats, and DEFINITELY needed overload springs plus heavy duty shocks.

 

Pierce - that looks like a overload LOL .. I did install some heavy duty springs from FCP and new shocks this past week ... my 940 had original shocks @ 209000 miles ... WOW! feels like a new car now ... The hitch I ordered from hitchanything.com should be here Monday ... cheapest I could find 158.00 class II ... I'll get that light controller and I should be good to go this week .. You said to stay out of OD? even at highway speeds? that is going to be some HIGH R's ... wonder what my mileage will drop to?

 

its not actually /that/ high revs to cruise 55-60 in 3rd (and when towing you really shouldn't go faster). you probably could get away with OD on dead level straight easy terrain with no headwind once up to speed, but the OD in the AW70/71 transmissions is not very strong, and virtually all vehicles, not just Volvos, say to stay out of OD when towing, even my former E150 van with the 5.4L V8.