Trailer Lights Wiring

Gentlemen,

I have a 2012 Tacoma with OFF-ROAD and TOWING packages. I'm trying to sort out the wiring for the trailer lights. On the truck, the pin that should be GROUND (round 7-pin connector) does not show continuity to chassis ground. My trailer lights only work if I connect my "safety" chain to the truck. Anyone have input on this? Any help would be greatly appreciated.

Gliderpilot

 

Not to be glib - but - how sure are you that you've identified the correct "ground" pin on the "tacoma side" of the 7 pin connector?

The wiring layout on these plugs isn't as standard as you might expect and the "ground" pin on your trailer may not match up to the "ground" pin on the Tacoma, in which case you'll need to either rewrire the trailer plug for your tacoma or wire up an adapter.

I tried to come up with a link to an authoritative diagram showing how the tacoma 7 pin plug is laid out, but came up empty.

 

Sounds like your trailer wiring is grounded to the same bolt that holds your chains to the trailer tongue so, when you connect the chains, it grounds the trailer. I would venture to say that your trailer wiring needs to be gone through.

 

Thanks for the responses, guys. I finally decided to put on my "retired EE" cap and do some serious digging.

The 7-pin round receptacle on the Tacoma is wired per standard practices. Apparently I didn't have a good connection to truck chassis ground with the ohmmeter (paint got in the way).

What I found was the wire to the ground pin on my trailer's flat 4-pin connector, after removing all the electricians tape, was hanging on by one strand (maybe). I'm in the process of replacing that connector and the "weekend warrior" splices that had been installed by the previous owner. Should be no problem once that's done.

Again, thanks.

Gliderpilot

 

I know you have already figured out the answer on this, but looking around I found a few diagrams that could help with the wireing, Here. It goes very well in depth with 4-way to 7-way wiring and help with finding out where everything goes. Hopefully this will help with any future endeavors.