Mystery Brown wire goes where?

Hi, I went down a dirt road and tore up the splash shield and some other stuff. Long story short I figured out the destroyed wires left hanging go to an ambient air sensor where it branches from the protective sheathing behind the radiator under the car. Problem is there are two wires that continue on to the passenger side. one is a skinny brown. The problem is there is also a thicker brown wire. I dont have any idea where this one goes. somewhere to the passenger side like the others or toward the ambient sensor or some 3rd option. How would I find out. I looked for hours with no luck. :frowning:

I found a picture of what it should look like with a sensor. mine is missing. New one in the mail.

Pictures of wires.

Where did you look?

Hint, look for wiring diagram for you xxxx year VW Rabbit with its @Ă·/_ engine and yyyy transmission. Google Alldata or Mitchell for services that, for a fee, give access to wiring diagrams.

Ya, first thing I did but I didnt find anything. I’ll just take it to a dealer if nobody knows. I looked all under the car and online. I watched bumper removal and transmission removal etc. to find what I did but never did see that thicker brown wire. Dangit.

Didn’t you just answer your own question? The first pic shows a brown and yellow wire attached to the missing sensor. You need a wiring pigtail with the connector for the air temp sensor. Probably can find one on RockAuto. Match the colors. Connect the wires. Done.

Yes, I already have that in the mail. So, those wires are accounted for along with two others that swing over to the passenger side. My problem is that there is a mystery brown wire that I have no idea where it goes. could go someplace new, over to the pass side, or towards the sensor someplace. I don’t know. could start putting it all back with a new splash shield when I get it all but that last thicker brown that is the same color as the skinny one that swings to the pass side is my problem. Its just a worn away wire with no home.

You are repeating yourself. The information you have shared is inadequate for us to help you. Good Luck with the dealer.

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The harness appears to go to something on the right side, it is not disconnected. Can’t you follow the harness? Open the plastic tubing, you might find the other half of the brown wire.

Hi, thanks for the understanding. I understand I’m not great at this. I took the wires out of the protective sheathing where they run to the yellow passenger side light (blinker?). The thin wires that run there look (lavender with a red stripe) and the (thin brown) wire that was cut but is there to reattach. and didn’t see the (thicker brown) wire. The wires that go to the Ambient air sensor are (brown with a yellow stripe) and (brown with a blue stripe.) The only wire I cant figure out is the Thicker Brown wire. It broke off at a branch point so could go anywhere. :frowning: Sorry battery died but that’s another issue. I have some pictures I’m trying to post from my phone where they all come from. Post here ASAP

Here are two pictures of where the damaged wires come from. First is the plug (its the one closest to the camera. The picture is taken from under the car looking up on the drivers side.

This second shows a branch I didn’t talk about before where the wires not talked about go to the Drivers side blinker (they are on the right side of the picture.) one looks (lavender with a black stipe.) This is all before the damaged part. You can see the thicker brown wire on the left side. I hope this doesn’t make it more confusing. You can probably just ignore this last post but posted just in case it helps.

Brown wires are generally ground wires on a VW. Does everything work; lights, windshield washer pump, horn?

For best help here, suggest to post make/model/year/engine/transmission, & any out of the ordinary options.

Ok thanks. After I do these tests I’ll post the results on my day off.
2007 VW Rabbit Automatic. I’ll check the engine and post that too. Thanks for the help.

The engine ID likely appears on the emissions-service sticker on the underside of the hood.

Sorry but I dont think these are blinkers as stated before. Anyone know for sure? They dont work either way.

2.5L I did the checklist and found the two lights on either side still dont work along with the windshield wipers. I used compression fittings that heat shrink. hope those are good. I think I did ok. The (brown with blue stripe wire) goes to the sensor wire 1 and the (brown yellow stripe) goes to number 2 if anyone ever needs this info. I will include a screenshot of a video called: " Volkswagen 00779 Outside Temperature Malfunction Fix and Diagnostics" 8min mark.

I put all the wires and sensors back together. All but the thick brown wire. Should I attach the broken thick brown wire to something like it’s a ground or what should I do next?

Are there wires going to them, or is there a hole for a socket/bulb?? If not then they are just reflectors…

IF you have no idea what the brown wire goes to or does, then you need to at least use a test light to see if it has power to it… IF you don’t know how to rig the test light so you can see it from inside the vehicle OR have someone else watching the test light then you can get a cheap back up alarm (BUA) and hook it to the brown wire and then ground the BUA and then get inside the vehicle and start it and turn on everything you can think of and hit every button to see if anything sounds the (BUA)… If nothing makes the BUA sound then ground it like Nevada said…
It also could just happen to be an extra wire in the harness for an option your vehicle doesn’t have… Sometimes it is cheaper for the OEM’s to build a harness for a multiple options section of harness then build the same harness with multiple different options and part numbers… Example with or without Fog lights…

BTW: A back up alarm is an awesome tool to have in your tool box if you do a lot of wiring and or trouble shooting while working by yourself… I used to use it a lot checking wiring at the back of the vehicle and trailer wiring also…