Wire Colors and Functions of Hopkins 7-Way Molded Trailer Wire Connector

Updated 05/09/2026 | Published 04/22/2014

Question:

I purchased this item for a past trailer and noticed the colors did not comply with what I understood to be standard trailer wire colors. Ended up crossing the colors in the junction box. Now Im working on a second trailer that was factory wired and they are using the exact same colors as this connector. This has me thinking that there is a second wire color-function chart out there. I checked the trailer wiring diagrams and it makes no mention of this second standard. Please clarify and if appropriate, supplement the wiring diagrams page.

asked by: Tim

Expert Reply:

There are two color code standards that are used in the trailer world. The Hopkins 7-Way RV style connector and cable, # H20046, that you referenced uses the RV Industry standard color code which is as follows:

White Wire - Ground
Red Wire - Left Turn/Brake
Brown Wire - Right Turn/Brake
Green Wire - Tail Lights
Blue Wire - Brake Controller Output
Black Wire - 12 Volt hot lead
Yellow Wire - Reverse Lights or Auxiliary Circuit

This color code is commonly found on camping trailers such as travel trailers and 5th wheel trailers.

Almost all other trailers such as utility, livestock, car haulers, etc. use a color code that is based on the standard 4-pin connector which is as follows:

White Wire - Ground
Yellow Wire - Left Turn/Brake
Green Wire - Right Turn/Brake
Brown Wire - Tail Lights
Blue Wire - Brake Controller Output
Black Wire - 12 Volt hot lead
Purple Wire - Reverse Lights or Auxiliary Circuit

These are the two common wiring color codes for factory wired trailers. It is very common that a previous owner or repair shop changed the wire colors because they simply used whatever wire they had on hand, so we strongly recommend tracing and testing the wires before making any final connections.

expert reply by: Michael H

Ed S.

8/8/2020

thank god you posted this! ive been struggling with this for 30 years. im right at the point of wiring a trailer and just about to re wire another. TWO color codes? damndest dumbest thing ive ever seen, but i guess you can teach an old dog a new trick. thank you!

Chris R.

8/18/2020

Awesome. I'm so glad we could help with this!

Dale M.

2/9/2022

@ChrisR like the way you put it out there and your right they used whatever wire they had lol witch nothing wrong with that in a situation but sorry 4 the next person to figure it out.

Isaac R.

5/9/2026

Thanks so much for posting.i can wire almost anything to my truck or trailer but when it comes to the trailer lights I always seem to strike out,lol.thanks again