My 2004 F-150 is losing it's mind and in turn I'm losing mine. The rear brake lights and license plate lamps are dim when the park/headlights are on, when you apply the brakes the lights get just slightly brighter(third brake light works fine).And...the turn signals work fine until you turn the park/headlights on and then they flash fast along with the license plate lamps? And with the lights on the signal lights will stop flashing if you apply the brake. This has come and gone three different times now, at different temps and times with no rhyme or reason. By the way it is a supercrew 4x4 with factory towing.Please help........THANKS!

 

You might check for a bad/loose/corroded ground wire. Maybe trace the wiring from the trailer plug back and see where the ground is connected.
Just make sure the surface is clean and the ground is making good contact.
Mike

 

check the ground strap inside lh frame rail
just forward of bumper bracket bolts
mitch

 

thanks guys i'll try that on turkey day--happy thanksgiving!

 

Happy Thanksgiving to you too!

 

THANKS---thank you Mike and Mighty chicken. It is/was a ground problem and although i couldn't find it....i tried the marine approach(adapt and overcome) and ran an additional ground wire to the negative wire going to the left rear tail/turn light assembly and ta dah it worked!

I DO APPRECIATE YOUR HELP---HAPPY THANKGIVING!!!

 

Great to hear. Glad you found the problem!