1973 - 1979 F-100 & Larger F-Series TrucksDiscuss the Dentsides Ford Truck
Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.
You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!
Hey guys, my most of the time, not all the time, when i turn the head lights on the left turn sinal light will stay on, and the turn signals dont work when the running lights are on. Any clue whats going on? Thanks guys.
This is a classic case of bad sockets up front. This shows up the way it does because both filaments in the 1157 bulbs share the same ground. Your turn signals don't work with the running lights on because of ground shift, due to the ground in the socket deteriorating. Your turn signal indicator in the dash comes on with the headlights on because your front running lights can't seek ground in the socket, so it backfeeds through the other filament and into the dash.
This should help you out. On the taillights, 3 wires, One ground and 2 power, one for running lights, one for turn signal. On mine they had a power wire to the ground and the running light power on the turn signal side of the bulb.
Stephen Georgia Chapter Leader
1979 F100, 351M, C6, long bed
Join the Georgia Forum- Click Here
HAH wow man i have the same problem except my blinkers dont work at all, and when i pull the switch into running light or headlight the right blinker indicator will light up. one day this past summer it stopped and the blinkers worked for several months and one day back to the same way. one thing i do notice is that one of the parklights is much dimmer than the other also, i cant remember if its the same side or not.
i just assumed i need to replace the 63 dollar ts switch which aint happenin lol!
im going to rewire all my front lighting harnesses as the wiring on this truck is so hardened that insulation will crack if i bend any wires around.
i also pulled both the flashers out one day to see if the light would go out and it stays on still too, idk if that tells anybody anything?
I suspected the socket, the drivers dide front is messed up, at the power teminals, i cleaned the ground prong and its shiny, lights on or off they dont work, however the hazards work cept front drivers. Randomly going down the road they worked then quit again. That was with lights off.
Yest i know that im an electrician, the socken ohms out fine, the old one did too after i cleaned the ground. However the terminals were screwed up and it was a pain in the rear the get the lamp in and out. Checking with power and ohms the lamp holder is fine, both filaments light up, but both at the same time, this is now the problem im trying to figur out right now. The turn signals i think is the swith, its hard to switch and feel gritty. As well as the turn signals randomly working.
Is there a fuse that is used for the lights in the front or the rear?
I've got some strange things happening under my dash with my wiring... likely from the P.O. chopping everything up real good...
1) My left turn signal pulsates at the same rate my truck pulsates (it doesn't idle consistent).
2) Some of the wires under my dash in the big cluster that goes directly behind the radio are starting to heat up really really badly and they're actually melting through the electrical tape and anything plastic that's touching the wires...
Any idea what's wrong with #2?
Number 1 sounds like it's just a socket or bad ground.
__________________ -= Caution: Man at work =-
1978 F-150 Lariat, Reg. Cab, Long Bed
351 Windsor (1972), 2-barrel, FMX, 2WD
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.