I have a 2010 coleman hybrid trailer and heres the problem, the break lights work and turn signals but for some reason not the running lights. Yes they did work back in April but not now and I have cked fuses in the trailer although I did not think that would be were the problem was. On my last trip my plug did some dragging so I have to replace it and hope I will find some lose wires are the problem but if not any suggestions? Since I knew I had a problem I did add extra reflectors on the trailer just in case but kept driving at night to a minimum and no Highway officer stopped me. So any ideas?

I suggest you start by checking the trailer connector on the tow vehicle with a test light to verify that each of the terminals is functioning correctly. Then at least you know if the failure is in the tow vehicle or the trailer.

7-pin Bargman Pinouts ... +12 vdc required on Pin 3 for the running lights to illuminate.

I carry one of these 7-way Trailer connector tester units in my RV Tool Box. It's always nice to eliminate the truck side when finding problems like this...I got mine from ETRAILER...I had to replace my trailer cord and plug one time and was an easy job as the leads were all color coded... Color for Color in the Electrical junction Box just under the frame... Mine used the large yellow twist on connectors...By the way I had to install a small relay and fuse in the truck fuse panel that was in an envelope in my 2010 Ford Truck glove box when I purchased it new. No markings on the envelope. This allowed the truck to provide 12V CHARGING for the trailer only when the Truck Ignition Key was 'ON'...Roy Ken

You will notice the Battery is on pin 4 and the Running lights are on pin 3, if you jumper between them, the running lights should turn on.

Most trailer light problems are poor grounding connections. Check that first.

Trailer running lights | Good Sam Community

12 Replies

Beverley_Ken
Explorer
Jul 26, 2016
Your profile indicates your tow vehicle is an F150. It is probably wired like our E450 or old Windstar for the trailer wiring. The trailer wiring harness is fused separately from the lights at the rear of the tow vehicle. Check the fuses under the hood of the truck.

Ken
AmericalVette
Explorer
Jul 26, 2016
SoundGuy wrote:
SoundGuy wrote:
7-pin Bargman Pinouts ... +12 vdc required on Pin 3 for the running lights to illuminate.

dougrainer wrote:
This is totally INCORRECT. The COLOR coding is not correct. Going to the Internet does not always yield the correct diagram. Doug

Dougie, buddy ... where did I say ANYTHING about colour coding? Read my post again, it says 7-pin Bargman Pinouts ... what is it about "pinouts" you don't understand? I further went on to say (to the OP) that in order for his running lights to illuminate there must be +12 vdc on Pin 3. In other words he needs to check with a VOM whether he has +12 vdc on Pin 3, if not those lights are not going to work. I made no comment regarding colour codes, that drawing is not my own invention, I don't own it, it was intended merely as a convenient means of illustrating 7-pin Bargman PINOUTS. Good grief. :S
:S
dougrainer
Nomad
Jul 26, 2016
SoundGuy wrote:
SoundGuy wrote:
7-pin Bargman Pinouts ... +12 vdc required on Pin 3 for the running lights to illuminate.

dougrainer wrote:
This is totally INCORRECT. The COLOR coding is not correct. Going to the Internet does not always yield the correct diagram. Doug

Dougie, buddy ... where did I say ANYTHING about colour coding? Read my post again, it says 7-pin Bargman Pinouts ... what is it about "pinouts" you don't understand? I further went on to say (to the OP) that in order for his running lights to illuminate there must be +12 vdc on Pin 3. In other words he needs to check with a VOM whether he has +12 vdc on Pin 3, if not those lights are not going to work. I made no comment regarding colour codes, that drawing is not my own invention, I don't own it, it was intended merely as a convenient means of illustrating 7-pin Bargman PINOUTS. Good grief. :S

The REASON I stated what I did was, some yahoo will look at your incorrect drawing and then take the 7 way apart and think that the wires(colors) are all on the WRONG pins. If you want to post a PIC, PICK the correct Picture. Doug
SoundGuy
Explorer
Jul 25, 2016
SoundGuy wrote:
7-pin Bargman Pinouts ... +12 vdc required on Pin 3 for the running lights to illuminate.

dougrainer wrote:
This is totally INCORRECT. The COLOR coding is not correct. Going to the Internet does not always yield the correct diagram. Doug

Dougie, buddy ... where did I say ANYTHING about colour coding? Read my post again, it says 7-pin Bargman Pinouts ... what is it about "pinouts" you don't understand? I further went on to say (to the OP) that in order for his running lights to illuminate there must be +12 vdc on Pin 3. In other words he needs to check with a VOM whether he has +12 vdc on Pin 3, if not those lights are not going to work. I made no comment regarding colour codes, that drawing is not my own invention, I don't own it, it was intended merely as a convenient means of illustrating 7-pin Bargman PINOUTS. Good grief. :S
Dr_Quick
Explorer II
Jul 25, 2016
I have owned 6 different RV trailers since 1966, (50 years) and every one of them have been wired like "Sound Guys" illustration.
dougrainer
Nomad
Jul 25, 2016
SoundGuy wrote:
7-pin Bargman Pinouts ... +12 vdc required on Pin 3 for the running lights to illuminate.

This is totally INCORRECT. The COLOR coding is not correct. Going to the Internet does not always yield the correct diagram. Doug
Black is 12 volt HOT
Green is running lights
Brown is RT
RED is LT
Yellow is center(not used)
WHITE is ground
BLUE is trailer brakes

The PIC color code is correct for a Boat Trailer 4 way flat.
Dr_Quick
Explorer II
Jul 25, 2016
If your brake lights/signal lights work I doubt that it could be a ground problem as they all use the same ground. If you jump form 3 to 4 on the trailer plug, like someone said the lights should come on. If not problem is in the trailer circuit and could be a damaged plug. If lights do come on, then use a test light from 3 to 4 on the truck plug so see if you have current there.
If you can not still get it to work, try this. take apart one of the running lights near the front of the trailer, the ground should be white, so go to the other wire which should be hot. Connect from battery + on trailer to hot wire and see if lights come on. If they do problem will be in connector or circuit between lights and connector.
Ava
Explorer
Jul 25, 2016
Most trailer light problems are poor grounding connections. Check that first.
Ozlander
Explorer
Jul 25, 2016
You will notice the Battery is on pin 4 and the Running lights are on pin 3, if you jumper between them, the running lights should turn on.
RoyB
Explorer II
Jul 25, 2016
I carry one of these 7-way Trailer connector tester units in my RV Tool Box. It's always nice to eliminate the truck side when finding problems like this...

I got mine from ETRAILER...

I had to replace my trailer cord and plug one time and was an easy job as the leads were all color coded... Color for Color in the Electrical junction Box just under the frame... Mine used the large yellow twist on connectors...

By the way I had to install a small relay and fuse in the truck fuse panel that was in an envelope in my 2010 Ford Truck glove box when I purchased it new. No markings on the envelope. This allowed the truck to provide 12V CHARGING for the trailer only when the Truck Ignition Key was 'ON'...

Roy Ken