No Running Lights

RoyB wrote:
I carry one of these 7-way testers that has the small LEDs on it in my tool box. This tells me the truck side is doing what it is suppose to do...

Then I know for sure it is on the trailer side...

This plugs into the 7-way receptacle on the back of the truck

Great idea. Here is a link on etrailer.com to the tester you pictured. $14 is pretty cheap insurance to do a quick check if issues pop up.

KJ

Had that problem my plug on the camper was missing a metal contact in the plug,Had to replace it.

I carry one of these 7-way testers that has the small LEDs on it in my tool box. This tells me the truck side is doing what it is suppose to do...

Then I know for sure it is on the trailer side...

This plugs into the 7-way receptacle on the back of the truck

Google Image

All of the DOT safety lights on the trailer are powered up by the truck 12VDC system.

Check your truck manual for the different locations for the various fuse panels... I think mine are in three different location... My main is just above the radiator under the hood... I have another one near the glove box inside the truck. I have another one behind the kick panel on the passenger side inside the truck...

The fuses for the 7-way and 4-way plugs usually have the word TOW in the description.

Roy Ken

LIKE2BUILD wrote:
Do you have a multi-meter? If not you can pick up an inexpensive one for about $15. Turn on the head lights of the truck and probe the truck end of the 7-way to check if there is power on the tail light pin.


If that checks out the issue is on the trailer. If there is no voltage on the truck you'll need to track down the wire or fuse that's faulty.

To check the trailer use a 12V battery to apply power and ground to the trailer end of the plug and see if the lights come on now:


If you still have no running lights, do as BB_TX said; open the junction box and find your ground and tail wires. Apply 12V and ground and see if you now have running lights.

If powering the plug gives you running lights the problem as to be with the truck. If the plug fails but you get lights at the junction box you need to either install a new 7-way plug or replace the umbilical. If neither the plug or the junction box gives you lights you could have an issue like Linnemj mentioned and have a bad ground or + wire in a fixture. As he stated, the tech had to go to each fixture until the problem was found.

Sorry there's no quick answer. This is just a process of elimination until the problem is found.

KJ

I think if you have your battery connected in your RV and jump across #3 and #4 on the trailer side you should have running lights if they are working properly. I know people sometimes do that when their parked in camp spots just to light up the outside of their RVs.

Do you have a multi-meter? If not you can pick up an inexpensive one for about $15. Turn on the head lights of the truck and probe the truck end of the 7-way to check if there is power on the tail light pin.


If that checks out the issue is on the trailer. If there is no voltage on the truck you'll need to track down the wire or fuse that's faulty.

To check the trailer use a 12V battery to apply power and ground to the trailer end of the plug and see if the lights come on now:


If you still have no running lights, do as BB_TX said; open the junction box and find your ground and tail wires. Apply 12V and ground and see if you now have running lights.

If powering the plug gives you running lights the problem as to be with the truck. If the plug fails but you get lights at the junction box you need to either install a new 7-way plug or replace the umbilical. If neither the plug or the junction box gives you lights you could have an issue like Linnemj mentioned and have a bad ground or + wire in a fixture. As he stated, the tech had to go to each fixture until the problem was found.

Sorry there's no quick answer. This is just a process of elimination until the problem is found.

KJ

I would start at the junction box under the pin box. Insert a jumper wire between pins 4 (+12v) and 3 (running lights) in your cord 7 pin connector. Then verify you either do or do not have 12 volts thru that J box. That will determine where to go next.

Google RV 7 pin connector wiring for standard wire colors. Black for 12 v and brown for running lights is normal.

When we had this issue it turned out to be one of the running lights had a bad ground. A RV technhad to check each light to find it. Best of luck!

Take an automotive fuse or flasher, and stick it in the FW 7 pin connector. Use the battery slot to running light slot. IIRC it is 10 and 2 o'clock. If this does not operate the running lights, go to the junction box by pinbox, open, look for loose wire/ wire nut.

Jerry

I've tested the trailer with my vehicle and my dad's. Both are newer trucks and both didn't engage the running lights. I've looked at my fuses and couldn't find a bad fuse.

Many Fords have a separate set of uses for the trailer connector. Some are under the hood on driver's side wheel well.