To start from the beginning, I recently wired in a LED Sequential tailgate light strip into my 7 pin wiring harness. From the beginning the truck acted strange. I had a rapid blinker on the driver's side but only when the lights were turned on. The passenger side was fine. I day was because it then began to act in sequence with the Sequential LED light strip. So in an attempt to resolve the issue I decided to eliminate the LED to light strip. After I fixed the original wiring, I was still having issues. The truck was basically acting like there was a burnt out bulb. For the record, there isn't. With the light strip disconnected & tge writing harnesses fixed I began to look for other possibilities. I ended up finding 2 blown mini fuses in the fuse box under the hood. So I replaced the fuses in hopes that would rectify the issue. Once again, it did not. With the lights off, the driver's side turn signal works fine. Once the lights are turned on it becomes a rapid blinking issue. Also the trailer wiring is acting weird. I have a trailer hitch light, that is suppose to light up when the brake is pressed but it now is illuminated when the lights are on, which I think is normal. But it flashes when the passenger side turn signal is engaged. It does not do it when the drivers side is engaged.
When the lights are turned on, the passenger side turn signal bulb is normal in brightness but the drivers side bulb looks like there isn't enough voltage getting to the bulb.
Basically I have about no idea what is going on. I fear my training hook up is now not working properly even though everything is basically back to original. What on earth is going on or could be the issue. Could it be a faulty relay? Is there a fuse that is tied to tge lights or turn signals that I am missing? Also, for the record I have checked the fuses in the cab & havre found any blown. Please, I basically have 2 weeks to get this fixed as I will need my truck at night to pull a trailer. So I need my lights, turn signals & trailer hook up to work property. Thanks in advance for help, suggestion or ideas.

 

@navysniper7 I'm assuming this is on your 2004 F150.

Is it an old body style (heritage) or new body style (2004-2008)?