Our Audis are a wiring nightmare with wires being routed everywhere. I made a very simplified wiring diagram of our cars so that you can get a perspective on the electrical system. As you will see from the pictures and the diagram, everything leaves from the fuse box/relay area located in the dash above the driver's left leg and to some extent to the ECU location and is routed throughout the car.
However they basically took four different paths to accomplish this. This makes for additional wiring which adds weight and complexity to the wiring of the car. I assume Audi as a logical reason for this, perhaps it is somehow a way to back up some of the electrical system so that if a side fails the other still works almost as if they wanted a dual or triple redundant system (which it isn't).
I’ll start with pictures prior to the stripping/removal of any of the electrical wiring so that you can have an overview of the wiring in the car. Here we go...
Looking at the centre console area from the driver’s side. You can se a multitude of electrical harnesses. The main and big one goes into a plastic conduit that goes back to behind the main steel beam that goes from left to right (structural) in the car and then runs left and then down to the fuse box area.
In the second picture we are looking from the front passenger’s door at the centre console. Now we can clearly see the main steel cross beam. Behind it run another harness from left to right. You can also see the harness that’s coming down from the centre area and down toward the left side. They all meet up and go towards the back of the car. Also notice the amount of harnesses and the wire within that go towards the centre of the car!
Looking in from the centre of the car towards the right hand side. You see the steel beam, the harness behind it, the one going down plus others. They meet at the bottom right and go back through the car.
My home made but very simplified electrical wiring diagram.
Finally where it all starts, the main junction. This is above the driver’s left knee area. Here we find the fuse box, the relays and others. Some will go back up and run towards other areas of the car and a big harness will go down to feed the left side of the car.
OK here’s another view/angle of the fuse box area. In this picture you can see that three harnesses are going towards the back of the car. However only two of them are actually going back there. One of them the one with the black rubber plug is heading to the right into a black box (top right of picture). More on this black box in the next picture. What I can tell you is that its usual location is below the car’s carpet near the rocker panel where all the wires are located in this picture.
Here’s the “black Box”. It’s called the convenience or comfort control box. Basically it controls all the power windows, power locks, alarm, interior lighting and exterior lighting and who knows what else? Again look at the amount of wires that go in and out of this unit. Of course all the wires come from the fuse box area go down to this black box and ten go back out to components around the car… Lots or wiring!
From one of three harnesses that runs back on the left side here we se the one that going to feed the rear lights, the trunk lock system, part of the emission system located in the rear wheel well and others.
That same harness splits upwards and goes to feed the defogger, third brake light and radio antenna.
When all is done all that will be required to feed the back end on the left side and including most of the rear right side is this; my new rear harness. I’d say that’s a pretty drastic modification, lol. This harness feeds the left safety belt pre-tensioner, the rear defogger, all the rear lights (L+R) because unlike Audi we decided to keep the wiring to a minimum. I decided not to use the rear fog light so it is not powered anymore. Both the left ABS wheel sensor and fuel tank gauge sensor run on the original wiring for now. In the future they will not be needed and thus removed from the car’s electrical system.
Now let us move on to the centre console area. As you can see some of the harnesses and wires have already been removed and cut. But still look at the amount of wiring left. More will be removed in due time! You can see the Hazard light/switch. Some of the other harnesses were for the radio and the HVAC system. Some of them wee for the ESP/Traction control and a lot of them are for the Airbag system. You can also notice a control module sitting right there in the middle and what would have been below/inside the main central dash cluster area. That module is part or the ESP system and it’s the roll/yaw sensor that ties into the steering wheel angle sensor for the ESP. You may have noticed the aluminium structure being put in place, well that will be for my new centre dash console.
Just a close up shot of the wiring in that centre console area.
In this shot we can see a main harness with lots of wires in it. It is terminated by a big yellow plug. This of course can mean only one thing… This is the main Airbag harness and every Airbag sensor in the car is wired and passes through here.
The Airbag sensor is connected to a fairly big module that controls the system. It is located here underneath the emergency/parking brake lever. Now since all I’m keeping are the safety belt pre-tensioners for both front seats, the steering wheel and right front passenger Airbags in working order, I will need to bypass all the other sensors by introducing in the system resistors that will fool the system into thinking it is properly hooked up.
Another module that requires way too much wiring (IMHO) is the Xenon light auto levelling system module. As I told you before one of the sensors that’s attached to the suspension is located on the rear left suspension. The other sensor is located to the front left suspension but Audi located the control module on the right side of the car and bolted below the steel cross beam underneath the front passenger Airbag. The steel brackets you see here are the ones holding the Airbag in place. You can also see that Airbag connector that I will need to keep the system activated.
The electrical rewiring job is not done yet and to be honest I’m not sure if it’s going to be completely done this year because the car needs to be running soon to get other work done to it (painting the cage/interior), finishing the brake modifications and so on. In just over one month from now I need to be on the track so things have got to start to move soon and fast. In any case here’s what was removed (wire wise) from the car so far and that’s from the left side only and mainly affects the rear portion of the car.
And this is what was removed from the right side only.
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How much did all the removed wiring weigh?
Originally Posted by dummptyhummpty
MY CAR IS ON AN EBAY BUDGET!! DEUTSCH REIS!
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