Trailer towing clearance lights do not work. All other lights and brakes work on trailer.

Congrats, you have found Ford's super secret fuse that drove everyone mad for years!

The turn signal bulb circuit on the trailer MUST match the towing vehicles turn signals. Example: Tow vehicle turn signal light is the same bulb as the brake light, then the trailer must match. If the tow vehicle has a separate turn signal (amber bulb located away from the brake light) then an adapter is available that will send the correct power to the trailer so everything works correctly. The adapter can be found an auto parts stores, RV supply stores and some truck stops too.

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Trailer Wiring Diagrams 4 Way Systems

4 way flat molded connectors allow basic hookup for three lighting functions; right turn signal / stop light (green), left turn signal / stop light (yellow), taillight / license / side marker (brown) and a ground (white).

4 way tow vehicle side.
4 way trailer side.
5 Way Systems

Same as 4 way system listed above but adds a extra blue wire for brake signal or auxiliary power. Used on pop up camper trailers or utility / boat trailers.
5 way tow vehicle side.
5 way trailer side.
6 Way System, Rectangle Plug 3/4 inch by 1 inch 6 way rectangle connectors right turn signal (green), left turn signal (yellow), taillight (brown), ground (white). The red and blue wire can be used for brake control or auxiliary. Use on a small motorcycle trailer, snowmobile trailer or utility trailer. Can also be used as custom wiring on trailers with 3 light/wire systems. See "Tow Vehicle Taillight Wiring" below.
6 way tow vehicle side.
6 way trailer side.
6 Way Systems, Round Plug

Round 1 1/4" diameter metal connector allows 1 or 2 additional wiring and lighting functions such as back up lights, auxiliary 12v power or electric brakes. Note: The black (sometimes red) 12v and blue electric brakes wire may need to be reversed to suit the trailer. Check with a test light or VOM. Uses: horse trailer, travel trailers, landscaping trailer, car trailer, etc.

6 way tow vehicle side.
6 way trailer side.
7 Way Systems

Round 2" diameter connector allows additional pin for auxiliary 12 volt power or backup lights. Uses: heavy duty landscaping trailer, car trailer, boat trailers, horse trailer, travel trailer, construction trailer, etc. Check with a test light or VOM.

7 way RV flat blade tow vehicle side.
7 way RV flat blade trailer side.

Most likely the brown wire from the trailer connector is connected to a constant battery voltage source, and it should be connected to the vehicle running light circuit, however someone might have wired the trailer connector up that way on purpose so that the trailer does not draw power from the vehicle running lights and possibly damage the vehicle running light circuit. (Dodge/Chrysler vehicles do have delicate lighting systems) Here are some images to help assist you, and the 4 way connector is the same as the 5 way connector just without the blue wire for the trailer brakes.

Take a 12 volt test light... the kind that has a spring loaded clip to hold the probe into the wire, and insert it into the wire just before the trailer plug, vehicle side. (Blue I think) If there is a connection, the brake should see it and you should have an indicator light. When you activate the brake the test light should lite up. If not, move up to the brake actuator and test the blue wire. If there is nothing at the actuator, check the black wire. It is power to the controller. If no power there, check fuses again. If it does pick it up at the plug, connect the trailer and test the trailer itself. First ground to the trailer and then to the truck. Most problems are ground wire related. Then move to the axle and test it there. For the brakes to work, and even show on the indicator, there has to be a ground and power to the brakes themselves. There are 2 wires to each brake... a ground and a power. Test across both wires to make sure you have power and ground. You can also hook another trailer to your truck or another truck to your trailer. Lights can work through trailer ball ground. Brakes can't. leave the trailer unhooked from the trailer and hook the wiring up and test the lights. That usually will indicate a good or faulty ground. Also make sure there is a GOOD ground to the truck frame/body. Also try http://www.etrailer.com/faq-wiring.aspx. They have a great website with lots of info. Hope this helps. Mike

check wiring on trailer

If this is a factory light harness for the trailer hookup on your Caravan. Look under the hood for a fuse box. Many 2000+ vehicles have this with separate fuses just for the trailer lights.

Then the problem is either with your trailer plug in, or the plug in on the truck. Use a test light to figure out which it is.

Battery junction box (BJB) fuse(s):

• 5 (30A) (trailer electric brake controller)
• 34 (25A) (trailer tow turn relays)
• 42 (30A) (trailer tow parking lamps)
• 44 (30A) (trailer tow battery charge relay switch side)
• 63 (15A) (trailer tow reversing lamps

I take it the blinkers and brake lights work ok when not hooked up to the trailer? If yes, then the wiring to the tow hitch is not hooked up correctly. How many wires to trailer pig tail connection? U can have up to 7 depending on what you tow. Check to make sure these wires are hooked up from the truck to tow plug correctly: 7 wired---
brown-Rt turn and brake light, yellow-backup, white-ground, blue-electric brake, green-tail running lights, black-battery charger, red-left turn signal and brake light. Let me know if u have something other than 7 wire, I'll get the wiring color and source info for u.