What exactly is a 'body ground'?
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What exactly is a 'body ground'?
I'm probing a couple of connections off the ecu connector and am unsure where to use as a ground. If I just touch the lead against bare metal anywhere, I don't get a reading. If I touch it against the air conditioner (?) ground bolt (just forward of the door, under the dash board), I get 10.5V. If I hold the lead in my hand and touch my feet against the ground I get 6.5V. I'm guessing that bolt that I think is a ground point is the right one? Not sure why I don't get a reading if I just touch the lead against the chassis anywhere else.
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From: long island, ny, usa
Re: What exactly is a 'body ground'? (vinuneuro)
little trick for you:
on any vehicle, the outer ring of the cigarette lighter is chassis ground.
but sometimes its hard to get an alligator clip to stay on that.
chassis ground refers to anywhere on the car that is BARE METAL.
automotive paint acts as an insulator and doesnt allow your meter/test light to get a proper ground for reading power.
look for a piece of the dash that is bare metal, if your on the passenger side, pull the plastic kick panel down and it should expose some bolts that go into the chassis, perhaps theres even a factory ground point back there.
youll know if its a factory ground point if theres a wire going to a bolt, and you can put the alligator clip on the metal connector that holds the wire to the bolt, OR the bolt itself.
basically the only part of the dash that acts as a ground is the beams that go through it to give structural integirty in the event of an accident, since they are WELDED to the bare chassis of the car.
DC power in cars flows in a circle. it starts at the positive terminal of the battery, gets used by the devices and the goes back to the negative terminal of the battery. so YOU cannot act as a ground since you are not part of that loop.
you need to put the ground connector of your tester "in the loop" to be "grounded"
hope this helps you.
-mike
on any vehicle, the outer ring of the cigarette lighter is chassis ground.
but sometimes its hard to get an alligator clip to stay on that.
chassis ground refers to anywhere on the car that is BARE METAL.
automotive paint acts as an insulator and doesnt allow your meter/test light to get a proper ground for reading power.
look for a piece of the dash that is bare metal, if your on the passenger side, pull the plastic kick panel down and it should expose some bolts that go into the chassis, perhaps theres even a factory ground point back there.
youll know if its a factory ground point if theres a wire going to a bolt, and you can put the alligator clip on the metal connector that holds the wire to the bolt, OR the bolt itself.
basically the only part of the dash that acts as a ground is the beams that go through it to give structural integirty in the event of an accident, since they are WELDED to the bare chassis of the car.
DC power in cars flows in a circle. it starts at the positive terminal of the battery, gets used by the devices and the goes back to the negative terminal of the battery. so YOU cannot act as a ground since you are not part of that loop.
you need to put the ground connector of your tester "in the loop" to be "grounded"
hope this helps you.
-mike
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