On my 1997 Lariat F150 with 4.6 ltr engine I only have power on the brown wire of the trailer connector underneath the rear bumper of the truck. No blinkers and no brake lights on the trailer. Everything works on the truck. I doubt that it is a wiring problem but rather a fuse problem, but I don't know what fuse I should check. Anybody have any suggestions what this could be? Thanks!

 

Do you have your owner's manual, they usually have illustrations of the fuse panel numbered detailing which fuse number is for what? If not here is your owner's manual https://www.ford.com/support/vehicle...owner-manuals/

Also corrosion could be an issue, especially over the 28 year existence of your truck. Cleaning all the contacts of both your truck and trailer connector are warranted, then spraying them down with WD40 or silicone spray will help them mate together better and reduce further corrosion. Moving back away from each of these connectors you may see a black wire which is typically the Ground wire going off to a connector and screwed into metal such as the frame. Unscrew these, lightly sand paper sand the connector and mating surface, reinstall the connector, spraying them down with WD40 or silicone spray.

Let us know what you find out. I met a guy on here that has an Automotive Electronics Technician and Electrical Engineer background that is a potential help contact.

 

Thanks for the link, but I do have my original manual. I checked the ground pin on the connector and it is good, so is the brown wire. It has power when head lights are turned on. I rubbed my volt meter probe hard against the yellow and green wires on the connector but no voltage on either one of them. I checked all the fuses in the fuse box under the hood and paid special attention to any fuse that included the word trailer. They were all good. I assume that the tow package connector with its wire harness is its own circuit and I also assume that it has one or more fuses. It would help tremendously if someone could tell me what fuses serve the tow package harness (if any) and also have a diagram, so I can troubleshoot/trace each wire from connector to where ever its ends

 

The guy with the Automotive Electronic Technician and Electrical Engineer background I mentioned forum name is "Bluegrass" I would send him a direct message, you can reference me if you'd like. He can likely help or at least point you in the right direction,

 

Thanks, I will do that

 

Also maybe repost in the "How to section Electrical" and "97-03" model sections. The more related sections you post to the higher the response should be.

 

Good idea. Will do

 

Strange, it won't let me start a thread in Electrical, Lights and Audio. It says that I don't have permission but I was able to repost in model year category

 

It has it's glitches, maybe post the posting problem to Community / Suggestions, Comments & Questions about the Forum that is suppose to be monitored by the moderators.

 

I have found most lighting problems between a truck and trailer are the ground connections. Is it a flat 4pin connector or round 7 pin? The 4 pin usually uses chassis ground which means when the trailer is connected to the truck it's grounded by the hitch itself. (especially on older vehicles) The 7 pin is usually used if you have trailer brakes or a battery that needs to be charged (like a travel trailer). Then there is a separate + and - carried thru the plug.
Do the lights work if you put 12V directly to them? That can be a pain to do because of the small pins. I use a small screw in each pin to allow better contact but only do one at a time as you don't want to touch two pins together, THEN you would be chasing fuses!
Hope this helps