If the voltage between real ground and the ground wire is not 0.0000 Volt, then the wire is not grounded properly.
a bad ground wire can ruin an alternator by not completing the circuit
Yes
A bad ground wire or ground connection.
ground wires are always black, the trigger is pink
Easy way is to run the large out wire to a ground, one post on the coil to a ground and one to positive. Do not allow the large wire to actually touch the ground, have it just above the ground so that you can see a spark. Warning: do not touch the large wire while the other are hot. It has a lot votage and could possibly cause you to get injured.
Bad bulb/Bad ground/Bad Wire
If you mean your gauges are going crazy, this is likely the result of a loose or bad ground wire. It could be the ground wire for your battery or any ground wire that is tied into the gauges.
The red wire is the positive wire. The black wire is the ground wire. The green wire is the speaker wire. The white wire is the auxiliary wire.
This could because by a bad ground wire. Check the ground wire to make sure it is connected properly and not corroded.
Red is hot, black is not.
A loose or bad ground wire can do that.
You can test your heater blower motor by connecting a ground wire to the ground. Connect a power wire, from the battery to the positive post. If the blower motor turns it is working, and if it does not it is bad.