7 pin to 5pin wiring

https://www.narva.com.au/resources/trailer-plug-wiring-diagram

https://www.narva.com.au/resources/trailer-plug-wiring-diagram

make a 5 pin plug ---- trailer wire ---- 7 pin socket
converter cable
5 socket 7 pin round plug
Pin 2 to pin 1 left turn wire yellow
pin 3 to pin 3 Earth return to body of car
pin 5 to pin 4 right turn wire green
pin 6 to pin 6 brakes light red wire
pin 7 to pin 7 Tail light Brown wire

if it is a rectangular 7 pin then
5 socket 7 pin rectangular plug
Pin 2 to pin 1 left turn wire yellow
pin 3 to pin 3 Earth return to body of car
pin 5 to pin 4 right turn wire green
pin 6 to pin 6 brakes light red wire
pin 7 to pin 7 Tail light Brown wire
refer to narva wiring diagrams to check
could use a 12v dc probe to sus out what the pins do.
might be able to buy a converter cable from a car spare parts shop maybe or make it yourself

If the trailer has electric brakes that are powered by a separate battery, you use a 4-pole to 5-pole adapter and connect the extra wire to the truck backup light circuit.
4 pin to 5 pin plug for trailer lights The Hull Truth Boating and Fishing...

its a different one then, unless you know how to wire it in so it works you got the wrong one

You have to many bulbs running for the size wire you can get into a 7 pin plug. You will have to up grade to a heavy vehicle plug which is around 2" in dia.. Next the stop light draw 25 watts each so if you have 3 trailers that ia 6 x25 watts x12 volts will indicate how many amps you are pulling when the brakes come on. Next you can change the wiring so that each bulb is connected in parallel not series that is the first 2 lights have one wire the 2nd bulbs will have a different wire out of the same pin and so on for the rest of the trailers. So what you will have will be say for 3 trailers the trailer plug will have wire to the first trailer and out of the same pin will be another wire that will go to the socket for the second trailer and so on That way the wire carrying the load will be the vehicle wire that you should have relayed any way. So you have a big current wire to the relay that is connected to the power pin of the socket. The relay is activated by the stop light wire to earth. This closes the relay and the heavy wire conducts current directly to the stop light pin of the first trailer and is piggy backed to the second socket and so on.. IN the end you will have only 2 bulbs working on each wire and not a multiple of bulbs drawing current on the one wire

suggest downloading the trailer pin standard for whatever number of pins your trailer plug has and tracing the wiring from the colors . The standard will tell you what color goes to what light and what pin number it should be on . Also 5 pin and 7 pin are different . You can plug a 5 pin into a 7 pin but the wiring is different .

Also check the trailer socket is grounded at the car body properly. As this can cause lots of weird symptoms.

I am guessing you mean the 7 pin trailer tow adapter.

the 7 pin RV plug itself



The 2005 trailer tow adapter wire diagrams

Sometime around 2000, GM started putting trailering pre-wire harnesses in the vehicle. Your truck may have this harness built in and would greatly simplify brake controller installation. Look under the glovebox and see if there is a wire harness tied off. There will be four wires in this harness, which should be run over to the steering column to use it. Most trailer brake controllers are compatible with this harness.
The four wires in the harness are: Red, 12vdc; black, ground; blue or purple, brake pedal; and brown or white, trailer brake wire to seven pin, four pin, or five pin connector at trailer hitch, if your truck came from the factory with a trailer hitch.
If you are adding the hitch and do not have the four wire harness, the under hood wires from your brake controller are Red, connect to one of the studs under the distribution box cover (the distribution box is on the driver's side against the firewall. Underneath the cover are two large threaded studs which are hot from the battery all the time); and the other wire from your brake controller would have to be run the length of the truck along the frame, tied off in several places, to the trailer hitch connector on the bumper. Follow the directions that came with trailer hitch wiring connector to connect this wire to the proper pin in the connector.
If this has helped you, great, and please remember to vote/comment.
Good luck!

Well the BEST way to fix that is take the Van AND Trailer to the dealer and make them check it over and get it working. Sounds like they screwed up., and are trying to blame the trailer. The 4 pins are easy to check Running lights, Left turn, Right turn and Ground. I suspect the 7 pin is wired wrong. I dont know why they put a 7 pin wiring plug on? Those are used for largeer trailers that need a battery feed and electric brakes

hi 1st check if light working 2u can not run all lights at same time; ok u need a rely4 pin or 5pin rely 85 86 pins to energize the rely pins 30 87 is used to energize the lights 87a is not used center pin; 3need tagl switch that have light ;find right wire for parking lights hookup 85to that wire 86 go to Negev 87 go to a15 amp fuse that gets power from B+ .30 go to plw lit now u can run low beam+plw or H beam+plw now u can run safly evriting

u must install the fuses for the system in he underhood heavy duty fuse box, it will be marked trailer tow