T&L Publications

Years ago the automotive market was flooded with electrical aftermarket accessories. Aside from the audio upgrade business, that market has slowed considerably since many of those devices are already incorporated by the manufacturer. When that business flourished, the installation instructions often included vehicle wire colors for connecting the accessory.

Today, is there any standardization or reference for vehicle wiring colors? Does any reference exist or is it catch as catch can with the manufacturers? People like Crutchfield make wiring harnesses for aftermarket audio, so this information must be someplace, or do they have to search through tons of wiring drawings, which would be near impossible!
OK car buffs! Is there any info out there?

If there is a standard it is probably written by the IEC and adapted by the individual manufacturers. In most cases you can find an applicable diagram online nowadays. I find the image search very useful. However I came up with several variations in my last search.

I find some of the colors hard to distinguish in older cars; red with pink stripe looks a lot like red with brown stripe sometimes when they are stained with oil, oxidized or otherwise dirty. At least red and black seem consistent

Maybe years ago, with the rather basic wiring, things were simpler. Now with almost everything wired to the max, consider the driver's door panel, there must be hundreds of individual circuits and considering there are only 10 primary colors, the combinations must be amazing! If each manufacturer standardized on a color code it might be more manageable. Add into that the discoloration because of aging, heat and grime, it is no surprise that military aircraft uses numbered wires rather than color codes.

aircraft wiring is like that also.. numbered. also the aircraft wire is Teflon coated to help prevent chaffing. going to a avionics shop or aircraft junk yard yields tons of free wire. usually they will give you all that you can haul away. the wire is usually a cladded copper mix.

Carrier Air Conditioning learned a valuable lesson many years ago. What they used to do was buy all yellow wire. They would then send it through an "Inking Machine". That was a series of motorized pulleys that drug the wire around some pulleys that were half submerged in different colored ink. The pulley in turn would leave 3 or 4 colored stripes on the wire every couple of inches.
Even the ground wires were inked green. They would ink an entire roll, usually 2500', at a time. Problems arose when the units were exposed to direct sunlight for years on end.
engineers told of units at an apartment complex, where some were shaded and some weren't.
The unshaded ones, all the inking faded and wires were all yellow. The shaded units were better, but fading.
For the last 10 years we were open, all the wires were factory colored.
Totally unrelated to automotive, just had to blurt it out....

Doing a stage lighting renovation project there were several hundred older color coded wires of mixed types. They came from the on stage lighting circuits and floor pockets and were to be connected to the new dimmer system's terminals. They were installed years ago with no real apparent logic to the colors or wire types and many of the wire markers were on the bottom of the cabinet. The cabinet was dark, so the apprentice rigged up a temporary lighting with on hand materials and set about making a wire chart and doing the connections.

On power up, we had pocket receptacles and lighting circuits all intermixed, some on the dim and others on un-dim channels, with no logic whatever. We reviewed the apprentice's wiring chart and wire colors, and it all seemed right. Since it was a computerized system with a programmable channel/load patch system, we suspected that the factory programming may be wrong. Ultimately, we discovered that, based on the wire color, they appeared to be a different color under the yellow colored stage lamps used by the apprentice. Some different colors were near identical but with white lighting, the incorrectly connected circuits were quite obvious.

Fortunately, since they were all load circuits, no real harm was done but it did set us back a bit; First trying to determine what the real problem was, and then with all the laughing after we found the cause. The correction went pretty quick after that but one color didn't change though, the face of the apprentice....It stayed red!