The 1.8T Wiring Harness Explained

[boy412]

Thanks for taking the time to do this Clint. The diagrams are all very well and good but its great to have a visual reference.

[AudiA4_20T]

np it was awhile ago but I figure it would help everyone

[AudiA4_20T]

Any one have info on this wire?



This is the last one I couldn't figure before searching and finding this thread.

snap a pic I can probably figure it out...

[nefkntym]

Any one have info on this wire?



This is the last one I couldn't figure before searching and finding this thread.

I am pretty sure that is the wire for the starter. There is one single pin black connector (big one) with a red/black wire. If it is not plugged in to the other side the starter does not turn over.

[nefkntym]

Will do when I am home from work.



Nope, The starter is all connected, I believe that wire you are talking about is bundled with the power cable running from the starter to the alternator. This one is not long enough to get to the starter.

No that is a different one.

[nefkntym]

I just went out to my car and pulled my side panel to take a pic. Are you referring to this connector?

If so, the starter will not turn over if it is not hooked up. I didn't research why, it was easier to plug it in.

[ForumEddie2]

Saw your post and thought maybe you could help determine what the Grey connector in the image goes to. This is the Left Connector Station in a 99 B5 A4.

[AudiA4_20T]

this would be in the Bentley manual, and I don't have a B5 one

[Denio24]

Here's an example of what's in the manual. You have to practice using the guide it has leading in to the wiring diagram section to be able to read it easily, but it's worth it. My trans swap would have been a nightmare without it, or I probably would have just bypassed the starter interlock relay, which I really didn't want to do.

Wow, I really second that manual whether it is in the Bentley or Elsawin for dealers. Once you learn to read those diagrams mapping out all the wires and components it is much easier to read than this thread. But nevertheless, it always great to have a visual aid!

[jbain2]

This helped me out a bunch. Thanks.

[AudiA4_20T]

np man, all about helping the community out

[gottaBdope]

I've mapped out all my wiring for both harness sides, but I have some discrepancy between the wire color on the diagram and the actual color of the wire. Would I be correct in thinking that the wire's pin placement on the plug is correct regardless of the wire color?

[diagnosticator]

I've mapped out all my wiring for both harness sides, but I have some discrepancy between the wire color on the diagram and the actual color of the wire. Would I be correct in thinking that the wire's pin placement on the plug is correct regardless of the wire color?

Usually, but not always. The terminal number in the harness connector is shown on the outline of the device/control module where the wire meets the outline, in the wiring diagram. Compare and confirm the harness connector terminal pin numbers that way.

[gottaBdope]

Usually, but not always. The terminal number in the harness connector is shown on the outline of the device/control module where the wire meets the outline, in the wiring diagram. Compare and confirm the harness connector terminal pin numbers that way.

Excellent, thanks for the response. I find that the only error is my starter/clutch interlock relay. I am a little confused about this because I thought that relay was part of the b6 harness...? So I'm not sure where I'm supposed to connect this wire...

[gottaBdope]

To clarify, can anyone hold my hand for this last wire please? I'm super confused about this "T9 BROWN pin 4" part...I can't seem to find the connector. I suck at wiring, so really I'm surprised I made it this far on my own (due mostly to the amazing stuff you guys had already posted), but now I'm for real stuck. Thanks.

Also, I do still have a detailed excel sheet for all the wiring I did and what I found from my wiring diagrams, if anyone wants.

[AudiA4_20T]

is this for the 2.7 swap?

[gottaBdope]

is this for the 2.7 swap?

yessir. I did all the body plugs, but I'm severely misunderstanding the aforementioned connector...

[AudiA4_20T]

yep. You need to understand how to power the harness too, not as easy as matching wires. Do you understand how the starter relay works? There are 3 wires (one is looped to make it easier).

[gottaBdope]

yep. You need to understand how to power the harness too, not as easy as matching wires. Do you understand how the starter relay works? There are 3 wires (one is looped to make it easier).

Short answer no. I know how relays work, but I'm confused on the implementation of it on this platform. Isn't the relay part of the 1.8t harness? Which would mean that either I have to pull that holder off the 1.8 harness and fab to the 2.7...or the 2.7 is supposed to have it's own and I don't think mine currently does...or it's actually housed in the b6 still and I just can't find it. I can stare at these wiring diagrams all day (and I have been for weeks now) but none of it means much to me without a physical correlation.

[AudiA4_20T]

Short answer no. I know how relays work, but I'm confused on the implementation of it on this platform. Isn't the relay part of the 1.8t harness? Which would mean that either I have to pull that holder off the 1.8 harness and fab to the 2.7...or the 2.7 is supposed to have it's own and I don't think mine currently does...or it's actually housed in the b6 still and I just can't find it. I can stare at these wiring diagrams all day (and I have been for weeks now) but none of it means much to me without a physical correlation.

My harnesses aren't so bad . Props to you for trying this though, shoot me a PM

[SaffrazM]

Guys,

Sorry for waking the dead, however i was in my engine bay a couple days ago and found a broken wire with a connector attached to it. Can someone help me figure out what this connector is? It's the little Blue connector in the 1st picture above where the ( "??????" )caption is, under the rear oxygen sensor connector. It's a round blue connector with some red on it.

Please help.

[SaffrazM]

Guys,

Sorry for waking the dead, however i was in my engine bay a couple days ago and found a broken wire with a connector attached to it. Can someone help me figure out what this connector is? It's the little Blue connector in the 1st picture above where the ( "??????" )caption is, under the rear oxygen sensor connector. It's a round blue connector with some red on it.

Please help.

Can someone please help with the above question? Come on folks, just in case yall didn't know which picture i was talking about, it's the 1st picture in the 1st post of this thread. Please help me figure this out.

[AudiA4_20T]

I believe that's a knock sensor. You don't have any codes?

[BerNur]

I have read somewhere that harnesses from VW work on our b6s, does anyone know which VW or have a part number to which harnesses work? It would be greatly appreciated I need one badly...

[badshovel]

I have read somewhere that harnesses from VW work on our b6s, does anyone know which VW or have a part number to which harnesses work? It would be greatly appreciated I need one badly...

It would definitely be from a passat if it does work

[BerNur]

It would definitely be from a passat if it does work

I'm looking at a Passat one right now it looks so identical its a 1.8 awm engine code

[AudiA4_20T]

I'm looking at a Passat one right now it looks so identical its a 1.8 awm engine code

I actually don't think they work. The body harness plugs are B5 ones

[BerNur]

I actually don't think they work. The body harness plugs are B5 ones

Hmm.. Looks very close.. I think I read a post on Audizine that some have used VW engine harnesses wish someone could chime in.

[AudiA4_20T]

Hmm.. Looks very close.. I think I read a post on Audizine that some have used VW engine harnesses wish someone could chime in.

Sorry but it doesn't look close. One of the biggest differences is the fact that the VW harness has 5 plugs instead of 4.

[customa4]

Can someone please help with the above question? Come on folks, just in case yall didn't know which picture i was talking about, it's the 1st picture in the 1st post of this thread. Please help me figure this out.

It would probably help to mention where you found the broken connector in your engine bay. Front, back, driver side, passenger side? Is it in a harness with other connectors, if so which ones.

[BerNur]

Yeah thanks for pointing that out as I was going of pictures..

[SaffrazM]

Hi CustomA4

I found the broken connector to the rear of the engine about 6 inches to the right of the Dogleg pcv pipe, i know that's pretty vague. i will try to take a picture and post for you guys, i did have some codes come up about knock sensor intermittent value and oxygen sensor voltage too low if i remember correctly.

I check online to find replacement knock sensors but the connector on the end of it is very different to the broken on ei am describing, also the oxygen sensors have more than 1 single wire on them. That left me kinda confused. Thanks for the help all and keep it comming.

It would probably help to mention where you found the broken connector in your engine bay. Front, back, driver side, passenger side? Is it in a harness with other connectors, if so which ones.

[SaffrazM]

will try to get a photo of it.

[Sejo_tt]

started adding 2002 B6 wiring to it

Hi some help please,
One of my fog lamps is not coming on shows up on the dash as bad bulb but i checked the bulb and its good, it's just not getting any power checked the wires back to the four pin connector behind the headlamp and I am getting power on one side of the connector the wire colors and numbers ( Brown-4 I believe is common, white and blue-2 and white and green-1 are the ( POS + ) for the lamps and the other is white and black-3 for the horn,) on the white and green i am getting 11.6v on the white and blue i am getting 1.5v so i am trying to trace the wires back checking them as i go but i am at a loss as to where to look for the next connection point is, Any help would be greatly appreciated thanks.

2002 A4 B6 1.8t

[audichris]

So is the 1.8t harness write up going to be the same as the 3.0?

[AudiA4_20T]

So is the 1.8t harness write up going to be the same as the 3.0?

unsure of your question

[blitz2190]

unsure of your question

I think he was expecting you to do the same type of explanation for the 3.0 harness.

[audichris]

pretty much if the repinning of the harness will be the same i have a 3.0 6 spd and im pickin up a 2.7 with harness and ecu off a 03
allroad with 51k on it for 700

[AudiA4_20T]

pretty much if the repinning of the harness will be the same i have a 3.0 6 spd and im pickin up a 2.7 with harness and ecu off a 03
allroad with 51k on it for 700

This thread has nothing to do with re-pinning harnesses. Please ask your question in the 2.7T thread, but regardless you cannot just "re-pin" to get a 2.7T. Shoot me a PM for more info

[JB5]

Hi Clint,

just finished matching up the wiring diagram between my 3.0 and the 2.7t body harness and was hoping you can look over it and let me know if it looks good. Read Blitz' wiring guide, the 2.7t build thread and this one have definitely helped me a lot. Dying to get this started this weekend.