I checked out both front turn signal sockets on my 77 F150, and each has a separate issue: one has a bad ground, and the other has a bad power lead (just one). If you look up aftermarket brand such as Standard Ignition, they show different part numbers for front and rear. Motormite makes one that they say works for both front and rear. I bought one of the motormite ones, and the damn thing just doesn't work right. If you connect ground and EITHER power lead, the light works correctly in flashing (for turn signal) or in solid on (for parking light). But when I hook both leads up, the turn signal does not work. Interestingly, when park lights are on, and turn signal is off, the indicator light lights up on the dash. then, when I turn the turn signal switch on, the indicator light goes off (but signal still does not work). I swiped a used socket (FORD OEM) off an old truck donor and it worked fine. Anyone ever have issues with these Dorman parts?

The wiring sequence was black to black (on socket), white/green to red (on socket), and brown to red (on socket).

 

Dunno about aftermarket parts, but...

D1FZ13234A .. Parklamp or Taillamp Socket-has 3 pigtailed wires attached.

Fits: 1975/86 F100/350 (front) & 1974/86 (rear).

Fits: 1978/86 Bronco front & rear.

Fits: 1975/86 Econoline front & rear.

Fits-front: 1971/76 Pinto / 1975/78 LTD / 1971/73 Mustang.

MSRP: $ 57.98 / ftepartsguy.com price: $ 41.75

The price is kinda high, but at least the part is the right one.