This past Saturday I welded on a new exhaust. Being the dumbadd I am, I didn’t unhook the negative battery connections and now I have a whole list of problems. First things first, I have no trouble codes of any type. Now let’s get into things. After I finished welding the exhaust, I went to leave and the truck was a no start. I eventually got it running with the help of brake cleaner and while driving 10 miles later it shut off on me. The turn signal lights were also every dime and switching form fast blinking to slow blinking. I have sense had the no start diagnosed as a bad cam shaft position sensor and bad fuel pump. I had air dog fuel lifter pump and ended up replacing with a fass system today. Back to the turn signals. As I was driving home today after replacing the fuel lifter pump, I noticed I had no brake lights when I hit the brake pedal except for the third brake light. However when I hit the brake light, the lights on my factory running boards light up solid. When I turn on the left turn signal, fronts work fine, the two mirror signal works, and the rear turn signal does too but the drivers side running board lights flash with the turn signal. When u do the passenger turn signal, the front works, the tow mirror works, not not the rear signal on the right. However the left running board lights flash along with the signal. I have no reverse lights. Please help. I have yet to check to see if any bulbs are blown. Will do tomorrow

 

Are we supposed to guess what you're working on?

 

my bad. It’s a 2005 f250 king ranch super-duty. 6.0 powerstroke

 

Sounds like your post title is the place to start. Bad grounds can definitely cause lots of problems, and stray electrons seeking a path to ground from welding might have cooked some of your grounds.

 

I'd suggest inspecting the grounding connection G400 at the back of the truck. Probably somewhere around the spare tire, inside left frame rail.