Is this trunk opener switch diagram negative or positive switched

Thread Starter

john2k

Joined Nov 14, 2019
146
I'm looking at the wiring diagram for the trunk opening switch on my car. I've attached the pic below. Can anyone tell me, based on that pic is the trunk switch system negative or positve switched? To me it looks like negative switched because it seems like earth is coming from the bottom and then being switched.

Here is the pic:

 

bwilliams60

Joined Nov 18, 2012
1,398
Most NA vehicle are positive switched except for maybe Ford Motor Company and Navistar who like using negative side switching. What kind of vehicle do you have ? Year/make/model and we can tell you more.
 

Thread Starter

john2k

Joined Nov 14, 2019
146
Most NA vehicle are positive switched except for maybe Ford Motor Company and Navistar who like using negative side switching. What kind of vehicle do you have ? Year/make/model and we can tell you more.
It's a 2007 Lexus IS250.

Me too.

FWIW, here's the diagram for a Chrysler minivan I owned. Hitting the switch grounds an input to the computer.
It does look similar to mine in that mine does look negative switched too. Is there a way to test it with a multimeter across the two wires?
 

bwilliams60

Joined Nov 18, 2012
1,398
The trunk liftgate works entirely off of the body control module. If you had a scan tool, you could actuate the liftgate from the scan tool or watch the inputs from the control switches.
The control switches are connected to the body controller on a low current line and when closed, they pull the signal to ground. The BCU then sends a signal to the Door lock Assembly to actuate the motor. From there it goes to ground.
 
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