What the heck is going on?

[1111ExpyEL1111]

2012 Expedition EL Limited. I have this accessory LED light that I want to have it turn on when the parking lamps go on and the headlights go on. So I get some of those "add a line" things where you put the original fuse in one slot and then a fuse for the accessory you want to add.

So I choose to use fuse 22 which is for lamps. But when I use this the lamps go out as they should but the LED accessory light stays on. No matter what I do it stays on. So I thought defective add a line thingy. So I try a different one and it's the same thing.

What is going on? Am I not using add a line right?

 

[JamaicaJoe]

did you measure the voltage at fuse 22? maybe it is hot with the ignition and accessory lighting relay full time?

 

[1111ExpyEL1111]

did you measure the voltage at fuse 22? maybe it is hot with the ignition and accessory lighting relay full time?

Sorry, didn't see this response until now. I have not checked it but I will. The exterior lamps and the interior lamps stay on for a while after you close the door but then they shut off. But the LED accessory stays on! I can't figure out why that's happening.

 

[1111ExpyEL1111]

did you measure the voltage at fuse 22? maybe it is hot with the ignition and accessory lighting relay full time?

I did not but I'll check

 

[dcsang]

You are tapping into the fuse block to power your LED accessory, which remains powered until the ignition is turned off and the vehicle's accessory timer disables the circuit. Your LED accessory should tap into a +12V source that is powered once the park lamps or headlights are turned on. A properly sized Posi-Tap is a good option.

EDITED: For clarity.