So I have a 1988 s4 convertible and as I was looking around the engine bay I found a wire coming out from the main harness right above the oil pressure sensor. It's a single yellow wire with a red stripe that leads to either a grey or white connector (looks gray but could be that way from grease over years) and then turns to a solid black wire. I've been chasing down a voltage drop problem for a while now as the volt gauge will bounce from 14v to 8v but sometimes hold 12v and 14v for no longer than 5 mins. I've cleaned the main engine bay grounds and installed a new alternator but still have the same problem so I'm starting to look at the surrounding wires. I'm not good with a volt meter or I'd check for some kind of voltage or continuity to the wire.

wire coming out of harness above the oil pressure sensor

wire after connector


Any help would be very appreciated!!!

 

It's for a signal conditioning capacitor which is mounted to the slave cylinder bolt originally(sometimes to the top flywheel inspection cover) to buffer the oil pressure signal circuit.