How to test for ground and other signals
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From: East Tennessee
How to test for ground and other signals I know how to test that I am getting volts to a wire. I am not sure how I test a ground wire using a DMM. I set the indicator to ohms, but I am not sure what I do with the leads.
What other tests should I do when testing wires for power and ground and whatever else?
Thanks.
What other tests should I do when testing wires for power and ground and whatever else?
Thanks.
On The Tree
Joined: Apr 2002
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From: Knoxville TN
Re: How to test for ground and other signals i asked the same question to my dad, who is an electriction. he said that you just hook the wires up on your meter just like you were looking for a 12v source (ie red lead to the wire that you are testing and the black lead to a ground)and it will show voltage. i tried this and it seens to work. granted he told me while he was on the phone at work. i think that i understood him correctly. hope that this helps you.
BTW where in maryville, i live in knoxville?
BTW where in maryville, i live in knoxville?
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From: Fremont, CA
Re: How to test for ground and other signals You can also test it using the ohm setting on your multimeter. You should get a very low amount of resistance, that would show there is a physical connection between the wiring you are testing. If you get an "infinate" resistance reading, then there is no connection, hence, no ground. I took some electronics classes <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
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Re: How to test for ground and other signals For the ground do I test the same way as volts but there is to be no power to the power wire and I am looking for 0 ohms?
Re: How to test for ground and other signals A few different ways.
1. Use Volt setting...hook one probe to a known 12v wire and then probe the wire in question. Should read -12v
2. Use Ohms...one probe goes to a known ground...the unknown wire will read 0 ohms.
3. Use Continuity setting..usually a buzzer on the multimeter...one probe is grounded and the the meter should ring/buzz when you find a ground ground.
Becareful though. Once you find a wire that shows a ground make sure thats what it really is. Door pin wires will show a ground with the door open (most cars) but show 12 volts with the door shut. Same with the illumination...shows ground until the parking lights are turned on. Starter wire will show a ground until cranked etc. If you really need a ground why not take it to the chassis instead of finding a wire?
Kevin
1. Use Volt setting...hook one probe to a known 12v wire and then probe the wire in question. Should read -12v
2. Use Ohms...one probe goes to a known ground...the unknown wire will read 0 ohms.
3. Use Continuity setting..usually a buzzer on the multimeter...one probe is grounded and the the meter should ring/buzz when you find a ground ground.
Becareful though. Once you find a wire that shows a ground make sure thats what it really is. Door pin wires will show a ground with the door open (most cars) but show 12 volts with the door shut. Same with the illumination...shows ground until the parking lights are turned on. Starter wire will show a ground until cranked etc. If you really need a ground why not take it to the chassis instead of finding a wire?
Kevin
