Ground wire

[joshpoints 10+ year member]

In the installation manual to the alarm that I bought it says that I should wire my alarm to the trunk wire that reads ground when the trunk lid is opened. I bought a voltmeter and I was wondering how you tell which wire is the ground. When I put the red wire on the gauge to the red/blackstripe wire on the light and the black gauge wire on the orange wire I get a neg. 12 volt reading. DOes this mean the red/blackstripe wire is the ground? If I switch the wires around I get a positive 12 volt reading.

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[eengrms 10+ year member]

I think it assumes you have a pin switch that turns the light on when the trunk is open, which grounds itself when the lid is opened. Do you? If so just attach to the negative side of the switch or whatever triggers the light.

 

[joshpoints 10+ year member]

Originally posted by eengrms I think it assumes you have a pin switch that turns the light on when the trunk is open, which grounds itself when the lid is opened. Do you? If so just attach to the negative side of the switch or whatever triggers the light.

That's the weird thing. I don't see any pins on the trunk lid anywhere. That's why I decided to wire to this light that turns on when the trunk lid is opened. Does that negative voltage rating that I'm getting mean that the one I have connected to the positive meter is actually the ground? Sorry I'm new to using these meters and what this stuff means. I have a limited knowledge in it right now.

 

[joshpoints 10+ year member]

Okay I followed the wires from the trunk light and one runs to the front of the car (battery) and the other runs to like a servo switch at the trunk at the key hole. I'm assuming the one at the key hole is the ground. Does this sound correct?

 

[joshpoints 10+ year member]

Originally posted by joshpoints Okay I followed the wires from the trunk light and one runs to the front of the car (battery) and the other runs to like a servo switch at the trunk at the key hole. I'm assuming the one at the key hole is the ground. Does this sound correct?

Ignore this question. the red/black is the ground wire for the light.