Wiring questions - Aux and/or 12v

OK, first of all that picture that you have on your post is wrong. The connector on the right is the one that belongs on the "car end," not the other way around. Take a look at this link, it shows all the pins and their wire colors:

TSB 08-33-96

So the number 4 pin (top right flat pin) is the battery (+) power. It should be hot at all times. The wire color is red/tan (12ga thick wire) If its not, check the number 7 fuse again, even though it looks good replace it anyway. I've seen some that look good, but are still bad.

If you still don't have power, then you either have a bad/loose connection somewhere along, or someone messed around with your trailer connector and screwed it up, somehow. If your connector is worn and corroded, this may be your problem, clean or replace it.

liamfm said:

Odd that the diagrams are different, but yes my #4 has power! So I'm guessing the #2 pin only has power when the brakes are applied?

Perhaps my truck is working just fine - that would be cool!

Click to expand...

Yup, I don't think there's anything wrong with your truck, you were just looking at that wrong diagram.

The #2 pin is the feed wire for the trailer electric brake controller. You need to buy a trailer brake controller and plug it in to the harness under your dash (there should be a plug there if your truck has the tow package). Once you have your brake controller installed and working properly, it will send current to the trailer's electric brakes via this #2 pin. Here is a link that shows some brake controllers, and if you scroll down a bit, you can also see the harness that plugs to the controller and to the plug under your dash ($14.95)

Brake Controller - etrailer.com

You can also read more about the types of trailer brakes here:

Hydraulic Trailer Brakes, Trailer Brakes, Trailer Accessories

dslsmoke said:

so if i have a trailer with a battery it will get charged by the black wire from terminal #4?

Click to expand...

Yup, that's the idea.