So the wifes car has thrown me yet another curve ball. While driving the car you can hear an electrical buzz and all the "idiot" lights on the dash (i.e. brakes, abs, open door, and so on) will flash and either stay on, and sometimes go off. Everything underneath the hood has a good ground. Has anyone ever had this kind of problem? I'm thinking it has something to do with the ground point behind the radio, but I don't wanna tear into anything until after this weekend (drills). This has drained the battery and torn through several alternators. It is a 91 tt automatic if that means anything.
A major supply line issue is my guess- either ground or +12v has an intermittent somewhere.
Other line to verify isn't having an issue is the connection from the +12v battery connector to the little fusible links black box in front of the battery. That thing is the main connection point for power to the rest of the car - a faulty line connection would cause some strange things too!
Some questions: Does the buzzing happen with the ignition set to ON without starting the engine? Is it consistent or intermittent? Try this, Disconnect the negative battery cable. Use a digital voltmeter to test the milliamp draw. To do this set the voltmeter to milliamps and connect the positive probe to the battery cable and the negative probe to the battery post. You should have no more than 35 (.035) milliamps. If you do you have a dead short somewhere and you need to start pulling fuses until the draw goes away. If this is good try connecting a 12ga jumper wire to the alternator housing and ground it on the engine block. Once that is done start the car and test the voltage to the battery. It should read 13.2-13.5v at idle and 13.5-13.8v at around 2k. Post what you find.
I know its been a while on this post but I found the problem (I believe). It turned out a wire on the ptu was bare and the PO had placed it just in front of the driver side fuse box. As soon as I taped the bare wire all the buzzing and idiot lights went away. Does this sounds normal