after 20 or so minutes my parking lights begin to flicker,what would cause this ?.head lights are fine. could it be a short or a bad switch ?

 

Do both sides do it, or just one? What about the side marker lights? Are they okay?
The marker lights and parking lights are all on the same circuit. If it's a switch problem then all of them should be acting up.
If just the parking lights flicker, I would first, check the bulb sockets, be sure the contacts are clean and free of corrosion and the contacts aren't weak and are making good contact with the bulb. Next check the ground connection. They are grounded to the radiator support. Be sure the connection is clean and tight. Check the wiring for any damage and it probably wouldn't hurt to put new bulbs in.

 

First, do all the things Mike suggested. If you can move the bulbs around in the socket and make them work or go off maybe you need new sockets. I just ordered a pair yesterday from here: Front Park Light Socket-Broncograveyard.com


I have lights that work most of the time but sometimes not. Yesterday I took them apart and found the bulbs to be very loose in the socket. Apparently that's my only problem.


Good luck solving yours.


Dennis

 

every parking light,side marker, clearance light & license plate light do it

 

All these lights are on the same circuit (BROWN wire) and are sourced from a separate pole of the headlight switch (vs. power to the headlights). If the headlights do NOT exhibit a failure, I would suspect the headlight switch in this case. An internal failure within the headlight switch could affect the parking lights without affecting the headlights. If the headlights acted up too, the diagnosis would be different.

 

new switch fixed teh problem. thanks ya'll .

 

Glad to hear you got it worked out.

 

Bronco Graveyard also failed to list all the other applications for this socket.

D1FZ-13234-A .. Plastic T/S Socket / Reproduced

1971/73 & 1977 Pinto / 1974 F100/350 from serial number T80,001 / 1975/78 LTD / 1975/79 F100/350 / 1975/91 Econoline / 1978/79 Bronco.

And as a taillamp socket for 1974 F100/350 Stylesides from serial number T80,001 / 1975/79 F100/350 Stylesides / 1975/91 Econoline / 1978/79 Bronco.

1973, 1974 F100/350 before serial number T80,001: The park and tail lamp bodies are metal, the individual plastic lenses screw to the bodies that have the sockets swagged into them.