this is really my forst time using a dmm. i wanted to know about negative and positive results. will the dmm actually show a negative if a wire i probe is negative?
If the com lead is on ground it will show 0V or close to it.
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sorry if i am sounding stupid about this but what do you mean by com lead. the reason i am asking is because i get the normal 12v when i am testing ignition wires and thing but what reading am i suppose to get when testing my trunk release. this is on a 92 lumina
Com lead usually is the black lead. It takes a while to really know how to use your meter.
What you can do when you test for a -trigger is connect the red lead to constant +12V and use the black lead to test the wire. When you do this the meter will read 0V at rest and 12V when the trigger is activated.
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Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.
I've been sick lately, sorry I won't be on much.
or if you take the "black" (unless you for some reason plugged red in to the com jakck) and chasis ground it, all (+) triggers will go from 0v to 12v. a (-) trigger will go from 12v to 0v. all numbers are rounded. 0v may be like .1158 or something and 12v could be anything from 12v up to 12.96v depending on how long ago the engine was shut off and what shape the battery is in.
chances are your trunk pop button will have 12v all the time on one side, and 0v on the other until you press the button. when you press the button the 0v should go to 12v, hence a (+) trigger. take the (-) trunk channel out put from the alarm/keyless entry/remote start (whatever brain you have) and use a relay to make it a (+) output. refer to https://www.the12volt.com/relays/page1.asp#n2p
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MECP certified installer