I'll post this in here as well and hopefully get some help.

Installed a new LED 3rd brake light a week ago - no problems.

Installed some new 3157 LED bulbs in my tails along with a EP27 flasher to cure the hyper flash.

My problem is since I put my tail LEDs in my 3rd brake light stays at half or less brightness all the time now like a running light, (when the truck is running, not when the truck is off and the keys are out).

I've switched out the flasher back to the stock one and the problem is still there.

WTF is going on?

 

Hey Red.

Try replacing the 3157 LED lights you installed with the OEM style and test the 3rd brake light. If that works its the 3157 lights...The F150s take a different taillight buld and this may be the problem.
I tried to order the OEM style taillights in LEDs and was told they were not available by any supplier, at least in Canada. See how that goes and let me know.
Good Luck
Topperman

 

You Might want to search under LED tail lights cause i remember someone else having this problem not too long ago and i think there was a fix for this but i dont remember who it was, sorry

 

OK, I guess I just need to install some resistors and get it over with.

Heres the question about those then:

Do I need 4 6ohm resistors, (one on each light), or 2 3 ohm resistors, (one on each tail light)?

I will be running LED 3157s in both the front and back lights.

If I only need 2 3ohm, then on what lights are they installed?

The reason I ask is because of this diagram:

 

So I think I have the problem solved.

Talked to a great guy at www.superlumination.com and he explained that the LED tails were letting some voltage passed and the 3rd brake light was showing that low voltage. He said I had to install a 100ohm resistor onto the 3rd brake light and that would stop the problem.

Also ordered a new EP27 through them as my first one had a horrible flash pattern where the first flash was extremely slow and the rest were ok.

So, just an FYI to anyone who is having similar problems with the 3rd LED brake light.

 

thanks for the input, thats what I thought was happening. I am going to live with mine the way it is.