HELP--My Exterior Lights Have Gone HayWire

[Starstream]

My exterior lights seem to be possessed by something and I really need some help.

To begin with, we've changed all the exterior lights of our '79 to LED's. I added a resister to the left and right blinker because my '99 Expedition needed the extra stuff to make things engage. I have installed a new 7-way harness on the AS, a new 7-way connector on the expedition and a new and separate fuse block just for the 7-way. I've checked all of the fuses in the Expedition and all is good.

The clearance/marker lights, back-up lights, electric brakes, 12volt charge and ground are all fine and working properly. But the brake and turn signal lights are possessed.

When I step on the Expedition brakes, all of the lights come on--including the license plate light. I can do Morris Code from just about every visible angle just by stepping on the brakes.

When I use either the left or the right turn signal the same thing happens. All of the lights, including the license plate, start blinking.

I've tested with a volt meter and nothing out of the ordinary.

I sure could use help in figuring out what is going on. What to double/triple check?

[Glenritas]

Take out the resistors and get a LED Flasher for the Expedition.

Grounds are real important with LED's.

The resistors may be back feeding the other lights, a diode in each may stop this.

[Starstream]

Thank you for the reply.

Is there a specific flasher diode that would work the best?

Thank you again