Wire color VS. Switch Designator

[Shuboxlover 482]

Why does the wire color in the socket of the wiring harness that plugs into the back of the key switch not match the wire colors of the wiring diagram? All the letters on the back of the switch match the wiring diagram, but the colors on the wiring diagram are not the same as what I have. I am fairly positive that the socket has not been tampered with. Do I go by the letters on the switch and where they go instead of following the colors.

Hope you understand what I am talking about. :thumbs:

[Duff 206]

For what it's worth (which may be nothing), the wiring colors on all three of my 312-8's were different from each other and at least two had OEM wiring harnesses. Only one of the three matches the colors in the wiring diagram I have in an original (not downloaded or reporduced) WH service manual for these tractors (300 and 400-series). Darned if I know, unless WH also used up lengths of wire they had laying around if they ran short of a specific color while making up a harness.

Anyone else run into this?

Duff :thumbs:

[KC9KAS 4,744]

The wire color is not important!

What IS important, is the size of the wire, and the location (where it is connected).

[pfrederi 18,957]

For what it's worth (which may be nothing), the wiring colors on all three of my 312-8's were different from each other and at least two had OEM wiring harnesses. Only one of the three matches the colors in the wiring diagram I have in an original (not downloaded or reporduced) WH service manual for these tractors (300 and 400-series). Darned if I know, unless WH also used up lengths of wire they had laying around if they ran short of a specific color while making up a harness.

Anyone else run into this?

Duff

I have found the same thing and I do not think they were PO modifications. Also I think the WH guys may have been color blind as their idea of tan vs brown and yellow vs orange (just examples) are not mine or my wife's (I had her look as color blindness is more common in males and women understand the difference between teal and green...I do not) idea of the color.... :WRS:

[Save Old Iron 1,571]

This is why its really important to learn two other colors - RED and BLACK

the colors of volt and ohm meter leads - they will never change and learning how to use them will prevent all sorts of guess work and confusion.

Let me know if you need help with measuring voltage or connectivity of the wiring and ign switch. The ohmmeter ignores the wire color and confirms its function.

[Duff 206]

Agree with you totally on the need for and knowing how to use a meter. We all should have one, and they aren't necessarily expensive. Easy to learn how to use 'em, too.

So here's a question - more of random interest than practicality, and not too far off the topic. In AC (household/industrial) wiring, generally the color codes are red/black/blue (depending on the number of phases involved) for "hot" lines, white for neutral, and green for earth ground. In automotive and other low voltage applications, the color coding doesn't seem to make any sense whatsoever, although I've never seen red as a neutral or grounding color. Are there any accepted conventions in low voltage wiring, or is it pretty much up to the engineer/designer in each application?

Always wanted to ask someone this question, and I figure somebody here might know.....

(Exception: Telephone wiring does have a very set - and complex- color pattern system, and my hat is off to anyone who can remember how it works beyond the four basic colors you find at the wall outlet in your house ! )

Duff :WRS:

[Save Old Iron 1,571]

Duff,

segments of the electronics industry adopt standards within their own realms.

Trailer light wiring is more or less standard.

Power supplies in PC systems, more or less standard, etc

Telephone industry and Ethernet cables have a "standard"

but look at your + battery cable on the 312 - why is it black ? and yet in your car (its closest cousin) it red ??

:banghead:

[chazm 413]

I'll bet that way back when if they ran out of a certain color wire they would use what they had. The wire color helps to identify the circuit on the wiring diagram.

I've seen a lot of auto/truck wiring diagrams & yes what I may see as one color may not be right - wire colors fade over time & if they use a tracer on the wire then its even more confusing.

Wiring can be a pain in the azz,

But like Save Old Iron said you need to know how to use a multimeter & a test light helps also.

If your wires don't match the factory diagram ,its back to old school & draw up your own diagram

Draw a pic of the ign. switch with the letters , then draw a line from each & write what color YOU have coming off of it. Follow each wire to see where it goes.

The multimeter will tell you if you have an open circuit or how much resistance on each wire to help locate problems

Compare your diagram to what the factory diagram has.

Just look for splices in any wires if somebody changed color wire.

Once you figure were everything goes keep it for further reference.

Chaz :banghead: