# New trailer wiring harness: All pins have constant 12v!!



## Studly (Feb 27, 2009)

I just installed a Curt trailer wiring harness (4 pin) on my 07 Honda Odyssey. Followed the directions to a T and had no problems. I put this wiring harness on so I can rent a Uhaul trailer. But since I don't have the trailer yet to test it with, I used my multimeter.

So to check the DC voltage, I connect the black lead on my multimeter to the big male prong on the harness (which goes to the white wire and is ground from what I've read), and then I used the red lead to test the three individual female pin slots. Problem is, no matter what I do, all the pins read 12v, even with the vehicle turned off. No change when I test the turn signals, brake lights, etc. -- all pins stay at a constant 12v.

The wires and insulation from the wiring kit and the harness and the plug all look to be in good shape and I can't see any cracks, nicks or places where there might be shorts. 

Does anyone who knows more about auto wiring than I have any advice? I made sure it plugged into my van's top right electrical slot, which is what the directions for this and all the other wiring kits say to do. I also installed the two fuses -- one inline and the other in the van's fuse box. I have the ground wire connected to a really solid ground screw attached to the frame.

Do I just have a defective wiring kit that is shorting out all the wires?


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## daveb1 (Jan 15, 2010)

I agree the big white wire is usually the ground, but have you verified that it actually is?


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## Studly (Feb 27, 2009)

daveb1 said:


> I agree the big white wire is usually the ground, but have you verified that it actually is?


Yes, when I touch the black lead to the grounded frame of the vehicle and then test the other pins, I get the same readings too.


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## DexterII (Jul 14, 2010)

Are you using a digital meter? I can't say that it could be giving you false readings in this case, but have seen it on AC readings. I don't know how to post pictures, but, for something like this, I almost always start with a simple 12 volt tester with a light in the handle, a probe, and a wire with a clamp to attach to any available ground. Then, if I want to get more precise, use an analog meter. Either are available for a few bucks at most hardware or auto parts stores, and probably big boxes.


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## Studly (Feb 27, 2009)

DexterII said:


> Are you using a digital meter? I can't say that it could be giving you false readings in this case, but have seen it on AC readings. I don't know how to post pictures, but, for something like this, I almost always start with a simple 12 volt tester with a light in the handle, a probe, and a wire with a clamp to attach to any available ground. Then, if I want to get more precise, use an analog meter. Either are available for a few bucks at most hardware or auto parts stores, and probably big boxes.


Yes, I'm using a digital one. Thanks for the tip. I'll try something else that's not digital.


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## Studly (Feb 27, 2009)

DexterII said:


> Are you using a digital meter? I can't say that it could be giving you false readings in this case, but have seen it on AC readings. I don't know how to post pictures, but, for something like this, I almost always start with a simple 12 volt tester with a light in the handle, a probe, and a wire with a clamp to attach to any available ground. Then, if I want to get more precise, use an analog meter. Either are available for a few bucks at most hardware or auto parts stores, and probably big boxes.


Hey, you're right. Just talked to tech support for the Curt wiring kit and they said that a multimeter will show 12v across all pins of the harness, but because there are no amps, you can't go by that because for the wires to be on, they need volts and amps. He too suggested I get a regular 12 volt tester with a light because that will show both amps and volts when it lights up. Thanks again for the help!


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