Hello everyone. I'm Manny and have a 99 f250 v10 gasoline. My brake lights and signals work great when I have switch off in the day time. At night when I turn lights on, it looks like I'm stepping on the brakes and my right signal does not work. If someone could help with that it would be great. Thank you

 

Take the rear bulbs out and clean them. If that doesn't work check the ground wire going to the sockets.

The running light circuit and the brake/turn circuit use the same bulbs but the bulbs have dual filaments, one filament for each. Problem is, these filaments are tied together inside the bulb on the ground end, and then go out on the ground wire. If this ground connection goes bad anywhere along the way to the frame of the truck, the current will go up backwards through the other circuit looking for a return path. This is what causes the other circuits to go wacky and glow dim and do things they are not supposed to.

 

Check the grounding studs behind the left and right kick panes in the cab.

 

Thanks, I'll check out both options