Multi-function switch battery drain


TJ Enthusiast
Supporting Member
Mar 31, 2023
East Texas
PO installed a multi function switch in the dash that is causing a battery drain so that my battery is completely dead after a couple of days of not starting the Jeep.

It is ran directly to battery terminals so I disconnected it for now but want to keep it because it controls a LED bar light on the front. It also has a connection for cell phone charging cable.

How can I reconnect it so that it only has power when Jeep is running?

I don’t necessarily like the switch but PO carved it into the dash so I am stuck with it.


Is there a relay in its circuit? It's easy to miswire a relay so the relay has to remain on to keep the item it's powering to stay off. In that case the relay is turned off to provide power to whatever it's powering. That will cause a constant battery drain when its device is not on, opposite to how it should be.
Could I just tap into the fuse/power box under the hood? I have some open fuse spots and a couple of open relay spots. Which would work best?
I'll betcha the power draw is coming from the USB port... it's constantly converting 12v to 5v.

I'd just run a wire from the cigarette lighter/power port to the USB outlet...then it'll be switched.

That or add another switch to the USB.

I have four USB outlets and just leave my Jeep on a trickle charger.

I ended up using a fuse tap for the positive wire and keeping the negative wire on the battery terminal. It took me several tries to find a spot that didn’t have constant power and the “Injectors” fuse seems to be working fine.


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