02 Outback trailer wiring?

I assume you have a 6-pin to 4-pin adapter between your OBW and trailer. I have used a trailer with my 97 OBW for many years and never had to use the power lead in the OBW plug.

-- Vic Roberts Replace xxx with vdr in e-mail address.

The adapter plugs into the car wiring harness down in the spare tire well, and is fed out the bottom of that space, ending in a flat 4 pin connector (three leads for the lights, one for ground). I don't recall how many pins were on the connector that plugs into the vehicle off hand. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There is a 6-pin socket attached to the car, so if you have a 4-pin socket going to your trailer then you have seem to have the proper adapter somewhere. You should see a rubber covered object larger than the rest of the wiring somewhere in the trailer wiring harness between the 6-pin plug and the

4-pin socket.

Back to your original question. If the trailer wiring from your OB works on two trailers but not on one, and if none of the lights on that one trailer work, then I suspect that the ground wire may be broken on the trailer with the non-working lights.

-- Vic Roberts Replace xxx with vdr in e-mail address.

Sorry, I now see that you said two other VEHICLES work with that trailer, not that two other TRAILERS work with your OB.

When you say that the trailer lighting connector shows current at the proper time, have you checked to make sure that the pattern is the same as with the other vehicles? How are you testing the connector - with a voltmeter (which measures voltage not current) or a test lamp? Is the second lead from the lamp or voltmeter connected to the ground pin on the OB trailer connector or to the chassis of your OB? If the latter you should test again using the ground pin on the OB trailer connector instead of the chassis. Was the trailer actually hitched to any of the cars used for these tests? If so, the ground connection might have been made through the hitch on some cars and not on others. This would indicate a bad ground lead on the trailer or in the wiring. Were the other cars domestic models that do not need an adapter or were they imports that also use an adapter. (Cars that share turn signals with stop lights do not use an adapter. Cars that have separate turn rear turn signals and stop lights need an adapter to combine these two signals to drive the combined stop light/turn signal light on the trailer.) Finally, can you find the converter in the lead running from the OB connector to the trailer connector?

-- Vic Roberts Replace xxx with vdr in e-mail address.

Measuring the _voltage_ (I'm assuming that is what you are doing . . .) is not the same as actually powering a light bulb; your voltmeter draws very little current compared to a lamp, and this can sometimes cause misleading readings. (I frequently have to demonstrate this to disbelieving students ;-) Try again using a homemade "test light" consisting of a couple wires connected to an automotive lamp.

To the best of my knowledge, this is true; certainly the OEM adaptor gets 12V from that 6 pin harness connector. As Vic suggests in an earlier post, you may have a bad ground, or the adaptor may have failed. Whatever, the "test light" described above will tell the tale.

If your adaptor will illuminate the test light while being connected between the 4 pin connector's ground pin and all three of the active pins, it will also power your trailer lights, assuming your trailer wiring is good. If it will light the test light while connected between the car's chassis and the active pins, look for a bad ground (the adaptor grounds to a screw somewhere IIRC, or the ground wire to the 4 pin connector may have been damaged). If you can't get the adaptor to light the test light at all, try another adaptor.

FWIW, I have had similar "strange" problems with trailer lighting that were finally solved by running an actual ground wire between the trailer connector and the lights (as opposed to using the trailer chassis as a ground).

Hope this helps a bit.

ByeBye! S.

Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101

The non-Subaru adapter I use on my '97 OBW does not connect to the 12-volt power lead in the 6-pin connector. But, depending how the switching circuitry is designed some adapters may use that pin. Designing the adapter to use the

12-volt lead would resolve the old problem of the flashing frequency changing when the additional lamp load is added. (That was solved in my OBW by using a heavy duty flasher instead of the standard one.)

The 6-pin connector in my 97 OBW had a ground lead. It is the lower right pin when looking at the end of the socket with the locking widget on the top.

I agree. You often cannot rely on the trailer chassis to provide a good ground for the trailer lights unless all the joints are welded. On tilt trailers and others with movable joints or trailers that are delivered in parts and are bolted together by the consumer the lights often require a dedicated ground wire.

-- Vic Roberts Replace xxx with vdr in e-mail address.

Since I was getting power on all three pins of the connector to both the ground wire and the vehicle ground (as per both volt meter and a test light), it seemed that things were working right at that point. Extra ground wires/connectors didn't seem to matter, neither did whether the trailer was hitched to allow a ground via the hitch. When I tried a different trailer, everything seemed to work right. So, I crawled under the trailer I'd been using, looking for problems there. The wiring harness splits into two wires for each rear light, which were joined to the short wires coming from the lights by crimp connectors. Somehow, it seemed all was good to those connectors, then bad beyond that. So, I cut out the crimp connectors, and soldered each of the wires, then taped them. For now, all is working. So it would seem that those were not solid connectors.

Since the trailer worked OK with other vehicles, but not with the Outback, it would seem that the possibility of the Outback putting less voltage or amperage to the trailer may still be possible...but it is apparently enough for now. Wait and see how long it all works.

Thanks for the ideas. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~