I'll believe mpmoore1979's fix works (kudos!). A question remains though is first, why it's necessary, and second, why it works.
My hypothesis: grounding and ground loops.
For about 100 years so far, manufacturers of cars (and airplanes) have cheaped-out by using the vehicle frame to cut the expense, weight, and complication of wiring electrical systems by nearly half. Assuming a negative ground system, a single positive wire supplies a current path from the battery to the device and the path back to the negative battery post is mostly through the body/frame. In ancient times BE (before electronics), this worked fine. In more recent times BD (before digital), less so. Today, AD (after digital), it's a mess.
Why? My old BD airplane is a good example. The ground/frame was a birdcage of welded steel tubing. Sitting on the instrument panel was a good ol magnetic compass. When you turned on the master switch, the compass would swing. Why? Current flowing through the frame would create a small magnetic field around each tube which affected the compass. Okay, that can be adjusted out, right? Sortof. But with each additional load, such as a radio, switched on, the current flow changed which in turn changed the compass reading. The point? With a negative ground system, one has a return path to the battery, but has no clue in how it accomplishes that task, other than it will, like a lightning bolt, take the path of least resistance including paths that may go through other-than-intended devices.
Experiment: With the car running, use a DVM to measure the voltage directly across the battery terminals, say 14.2V. Then start measuring across red & black wires and red-to-ground at other locations. Don't be surprised to get readings other than 14.2V. In the majority of cases, it's because the load in that circuit is pulling the voltage down. Now get long extensions for your DVM leads. Connect one to the (-) battery terminal. Put the other at locations around the car where there are grounding points to the frame. Good chance you will find some showing a voltage reading between that point and the battery terminal when they should be the same. The term for this is ground loop.
The unit Volts is always a reference between two points. Volts (the car) have batteries in the back and most of the electronics in the front. Since there are not individual ground wires for each device, and many of the devices are "grounded" at different places, the situation is ripe for ground loops, with currents flowing between places that should have been at the same voltage potential (namely 0).
BE, a volt and half an amp is unlikely to matter. BD, more so. AD and millivolts and milliamps going where they shouldn't can take the car down.
Compounding issues is that GM and others seem to have forgotten how to do basic electricity. The Volt's ground connections are crappy. The body is thoroughly painted before ground connections are made and they depend mostly on little star washers to cut through the paint to metal. My car had a host of increasingly weird problems until I pulled apart every ground connection (disconnect the battery ground while doing this) I could find, sanded off some paint and reconnected with a little dab of dielectric grease to protect against moisture and rust. Ever since = perfect.
My hypothesis: grounding and ground loops.
For about 100 years so far, manufacturers of cars (and airplanes) have cheaped-out by using the vehicle frame to cut the expense, weight, and complication of wiring electrical systems by nearly half. Assuming a negative ground system, a single positive wire supplies a current path from the battery to the device and the path back to the negative battery post is mostly through the body/frame. In ancient times BE (before electronics), this worked fine. In more recent times BD (before digital), less so. Today, AD (after digital), it's a mess.
Why? My old BD airplane is a good example. The ground/frame was a birdcage of welded steel tubing. Sitting on the instrument panel was a good ol magnetic compass. When you turned on the master switch, the compass would swing. Why? Current flowing through the frame would create a small magnetic field around each tube which affected the compass. Okay, that can be adjusted out, right? Sortof. But with each additional load, such as a radio, switched on, the current flow changed which in turn changed the compass reading. The point? With a negative ground system, one has a return path to the battery, but has no clue in how it accomplishes that task, other than it will, like a lightning bolt, take the path of least resistance including paths that may go through other-than-intended devices.
Experiment: With the car running, use a DVM to measure the voltage directly across the battery terminals, say 14.2V. Then start measuring across red & black wires and red-to-ground at other locations. Don't be surprised to get readings other than 14.2V. In the majority of cases, it's because the load in that circuit is pulling the voltage down. Now get long extensions for your DVM leads. Connect one to the (-) battery terminal. Put the other at locations around the car where there are grounding points to the frame. Good chance you will find some showing a voltage reading between that point and the battery terminal when they should be the same. The term for this is ground loop.
The unit Volts is always a reference between two points. Volts (the car) have batteries in the back and most of the electronics in the front. Since there are not individual ground wires for each device, and many of the devices are "grounded" at different places, the situation is ripe for ground loops, with currents flowing between places that should have been at the same voltage potential (namely 0).
BE, a volt and half an amp is unlikely to matter. BD, more so. AD and millivolts and milliamps going where they shouldn't can take the car down.
Compounding issues is that GM and others seem to have forgotten how to do basic electricity. The Volt's ground connections are crappy. The body is thoroughly painted before ground connections are made and they depend mostly on little star washers to cut through the paint to metal. My car had a host of increasingly weird problems until I pulled apart every ground connection (disconnect the battery ground while doing this) I could find, sanded off some paint and reconnected with a little dab of dielectric grease to protect against moisture and rust. Ever since = perfect.
