I have a 98 f150. When the tail light bulbs are cold the D-side brake/hazard light does not work. The center and P-side do work. I turn on the D-side blinker it works. The brake/hazards at this point will work. Let the bulb cool off and the D-side brake/hazard stops working. Tried replacing the flasher and D-side bulbs but this did not fix problem. Has anyone ever seen anything like this? Could there be a problem with the MFS? Or maybe a replay?

 

Have you checked your plug for a crack that might cause a loose fit? Spray some electrical cleaner in there and look for worn spots in the wire.

 

thanks for reply. I figured it out. The turn signal switch (MFS) is bad. When i wiggle the turn signal lever or turn on high beam the tail the brake lights work. who would have thought that the brake light would go through the turn signal switch.

 

Thanks for the help man! Buddy of mine was having a similar issue. Don't worry... The deeper you dig into these engines the more illogical the build seems. (to an extent) Cheers!

 

it's all the same bulb for brakes and turn signals, and the 4 way flashers.