QuestionQUESTION: I got the new stereo and the aftermarket wiring harness but the colors on the harness are in totally different places from the ones in my car and also different colors. The five wire plug on my car is the power plug and the eight wire one is for the speakers. The after market one has a four wire plug for the speakers and a ten wire plug for the power. Although they do plug into each other they are obviously not going to work. What can I do to fix this? These are the only plugs that fit the harness, the others on the after market harness are not the right size.
ANSWER: Hi Sherry,
Without seeing your harness, it's difficult to tell if you're dealing with something unusual in your Tercel. The standard Toyota 2-piece harness has been used for many years; I haven't seen a 2-piece Toyota plug that varied from the standard type. In the typical Toyota plugs, the larger plug includes power and ground wiring along with the front speaker wires. The smaller plug includes the rear speaker wires, and an illumination wire.
Here's what I have listed for the factory wire colors in your car's radio harness:
Battery: blue/yellow
Accessory: gray
Ground: brown
Front left (+): pink
Front left (-): violet
Front right (+): light green
Front right (-): blue
Left rear (+): black
Left rear (-): yellow
Right rear (+): red
Right rear (-): white
As you can see, you shouldn't expect the Toyota factory wire colors to match the after-market harness colors. If your wires don't seem to match up correctly, I'd suggest getting out a multimeter and see if you can verify the wire functions that way. However, if the after-market adapter harness you have matches the factory plugs, then I'd be surprised if it didn't work without any modification. I haven't run into a 2-plug Toyota that varied from the standard pin layout.
Hope this helps!
Brian
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QUESTION: The biggest problem is that the after market harness has a four wire plug as the smaller one and a ten wire plug as the larger one whereas the original one in the toyota has a five wire plug as the smaller one and an eight wire plug as the larger one. I already have the list of factory wire colors but the number of wires in each plug is not the same. I hooked them up faithfully just as they were listed but nothing works at all.
AnswerSherry,
What you're describing is actually pretty common. Many factory radio plugs contain wires that aren't required for an after-market head unit, so the after-market harness manufacturer often doesn't bother to place a wire there. For example, in a typical Toyota harness, the smaller 5-pin plug contains four speaker wires, and one illumination wire of a type that's rarely used in an after-market installation. The harness manufacturer will sometimes just include the four speaker wires, and leave the illumination pin empty. If that's the case for you, the small after-market harness should have a green, violet, green/black and violet/black; and they should match up with black, red, yellow and white, respectively, in the factory radio plug.
In the larger plug, you have a similar situation in reverse: the after-market harness includes wires to activate a powered antenna, but if that feature isn't equipped in your vehicle, then the factory wires won't be present. In that case you may have blue or blue/white wires in the after-market harness that line up with empty pins in the factory plug.
From what you're describing, it sounds like the new head unit isn't powering up at all. In that case, you can limit your troubleshooting efforts to just the power and ground wiring (at least for now). All the power wires should be in the larger plug, and they should match up like this:
The after-market yellow should match with the factory blue/yellow
The after-market red should match with the factory gray
The after-market black should match with the factory brown.
The after-market orange (or orange/white) doesn't matter as far as powering the head unit is concerned.
The rest of the wires in the large plug should be speaker wires.
It's possible that there's no wire in the factory plug that matches with the black ground wire on the after-market harness. In that case, you may have to route the after-market deck's ground wire directly to a metal grounding point in the dash cavity.
Otherwise, if the wire colors match up like they should, then you'll need to figure out why one or both of the power wires isn't getting power. The most common problem would be a blown fuse in the vehicle fuse box. Each power wire should have its own fuse somewhere in the fuse panel, although they might not both be labeled as radio fuses.
If the wires in the harness don't match the factory wires as they should (or if the wire color listing turns out to be incorrect) then you'll really need to have access to a digital multimeter for any further testing. With a multimeter, you can identify the function of each wire, regardless of the color or pin position; and modify the harness as needed to match the correct after-market wires with the correct factory wires.
Hope this helps!
Brian
