You know that wire on the firewall ground connection behind your intake manifold that falls apart on every S4?
It is the ground for the Secondary Air Injection motor (located underneath/behind the p. side aux radiator). And it is absolutely terrible shape (brittle shielding) through the entire harness.
Also, the other wire from the SAI motor, a red on that runs all the way through to a relay connection under the ECU, is in equally as bad shape! You just can’t see it since it is inside the loom.
I found this on my harness. Green in the brown ground connection wire that everyone tapes up. Yellow arrows point to the red wire from the same SAI motor plug. I even bought a Used harness… splitting into that one, the same wires - BOTH of them - have the very brittle and disintegrating shielding.
http://audirevolution.net/addons/albums/images/183816628.jpg
http://audirevolution.net/addons/albums/images/409918254.jpg
Not sure the point of the post really other than an FYI. 