Tracing cables on car

Thread Starter

john2k

Joined Nov 14, 2019
146
Does anyone have any tips or ideas on how I can trace a cable from one point? I have a courtesy lighting circuit in the front doors. And I want to tap into the power source. So instead of running a wore from the door and through the tight grommet of the door hinge, I would prefer to tap in to the cables outside of the door where it's coming from anyway. But there are soo many wires and I don't know where to even begin. Ideally I don't want to pierce the cable sleeve or anything.

I got myself one of those toning devices where I plugged in the wire but the minute I plug the crocodile clip of the toner into the wire then the toner almost stops toning at the crocodile clip end so that doesn't seem like an option
 

wayneh

Joined Sep 9, 2010
17,152
Does anyone have any tips or ideas on how I can trace a cable from one point? I have a courtesy lighting circuit in the front doors. And I want to tap into the power source. So instead of running a wore from the door and through the tight grommet of the door hinge, I would prefer to tap in to the cables outside of the door where it's coming from anyway. But there are soo many wires and I don't know where to even begin. Ideally I don't want to pierce the cable sleeve or anything.

I got myself one of those toning devices where I plugged in the wire but the minute I plug the crocodile clip of the toner into the wire then the toner almost stops toning at the crocodile clip end so that doesn't seem like an option
The wiring diagram has that kind of detail and it's worth your time trying to find it. It may not be easy, but most cars are out there somewhere. Owner forums for your exact vehicle are the place to start.
 

shortbus

Joined Sep 30, 2009
8,568
How new of a car? Most cars from this century use the body control module for courtesy and dome lights. If there is no little button on the body, surrounding the door opening, it probably is using the BCM. Even the old cars with the button turned on the lights when that button switch grounded when a door opened. Is there a reason you just don't get your power from one of the light socket wires?
 

bwilliams60

Joined Nov 18, 2012
1,398
Not sure what a toning device is but as @shortbus says, most newer vehicles ar eusing low current, low voltage wiring for body control and tapping into one of them will do more harm than good. Post up the device and year/make/model of car and lets see what we can figure out.
 
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