I have a 1974 F-100 ranger. I have been dealing with an electrical issue for quite sometime now and have no clue what could be the cause. I am not an expert in the electrical field. The rear tailights will both light up when i turn the lights on and will stay on but the minute i touch the brake the right one goes out and the left one stays on. The blinker works for both of them and like i said both lights work and stay on but only when i touch the brake does the right one go out but the left stays on. Could it be a grounding issue or i dont even know. Any help would be great thanks!!

 

I would say almost certainly a grounding issue.

Always carry a electric multimeter in your tool kit invaluable at check all electrical faults!

Happy motoring.

 

remove tail lites & bulb sockets
after removing bulbs look for dark spots in side
sockets
will most likely need replacement t-s sockets
any parts store & a few butt connectors

 

First, change all the rear bulbs and retest, I have seen the filament inside the bulb fall across the other and cause strange problems.

okie

 

Thanks for the replies, i will let you know which one works