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Need help Turn signal / Backup lights not functioning
New member but avid reader.
I have a 1977 F150 short bed 351 c6 3 on the tree. I’m at a loss on where to go from here. I’ve tested what I have found in the forum but still can’t wrap my head around why the turn signals won’t activate.
I have established the following facts.
dash lights work
Headlights work
High beams work
Hazard switch, activates brake lights and grill turn signal lights
Hazard flasher is in working order
Turn signal flasher replaced with known working flasher
Side markers are LED
Neutral safety switch is on the steering column
Neutral safety switch does limit starting the vehicle when in park.
Tail lights, work and share same ground with backup lights
Back up lights are new and appear to be in working order
Backup light housings appear to be in good shape
Pressing the brake pedal activates brake lights
Turn signal switch behind steering wheel is new
Activating a turn signal has no effect(no indicator light on dash, no park or side marker or brake lights turn on)
I need some help from someone far more knowledgeable and experienced than me. I can supply photos and additional information and I greatly appreciate any and all help!
Last edited by 77JadeF150; Feb 22, 2025 at 01:10 PM.
Fuel gauge is below empty, so I have to ask, was the key on when that indicator was dark?
Signals will only work with the key in and switch on. Back up lights will only work with key in and switch on.
Four ways will work without the key in. Head or Park lights will work without the key in. Brake lights will work without the key in. Side marker and instrument lights only come on with head or park lights.
Your "Neutral Safety Switch" may need adjustment. It also controls the Back up lights.
You wrote
Back up lights are new and appear to be in working order
in your post ....
.... but in the thread title you say
Need help Turn signal / Backup lights not functioning
Fuel gauge is below empty, so I have to ask, was the key on when that indicator was dark?
Signals will only work with the key in and switch on. Back up lights will only work with key in and switch on.
Four ways will work without the key in. Head or Park lights will work without the key in. Brake lights will work without the key in. Side marker and instrument lights only come on with head or park lights.
Your "Neutral Safety Switch" may need adjustment. It also controls the Back up lights.
You wrote in your post ....
.... but in the thread title you say
ok further clarification,
the backup lights do not illuminate when column shifted into reverse. But the bulbs look to be brand new and intact filaments.
new discovery:
with the key in and ignition turned to on… while depressing the brake the tail lamps are on. When I flip the turn signal switch to either right or left the respective tail lamps turns off.
ok further clarification,
the backup lights do not illuminate when column shifted into reverse. But the bulbs look to be brand new and intact filaments.
new discovery:
with the key in and ignition turned to on… while depressing the brake the tail lamps are on. When I flip the turn signal switch to either right or left the respective tail lamps turns off.
You have a bad ground from the sound of it. The turn signal switch interrupts the brake light on the side you signal, What you are likely seeing when you are depressing the brake and seeing tail lamps is likely brake lights lit up that are dim because there is a bad ground limiting current. New signal switch too, might pay to double check your connections in that curved connector under the dash.
You have a bad ground from the sound of it. The turn signal switch interrupts the brake light on the side you signal, What you are likely seeing when you are depressing the brake and seeing tail lamps is likely brake lights lit up that are dim because there is a bad ground limiting current. New signal switch too, might pay to double check your connections in that curved connector under the dash.
Tail light intensity is normal and running lights all turn on when the light **** is at half pull. I’m ordering all new sockets for each corner since the ones there have some finicky wiring. They don’t want to be bent certain ways otherwise the light cuts out. I’ll reground all the lights and push the wires into the curved connector to ensure they are all seated well.
Which color wires am I looking to pay special attention to in the curved clip?
Short abbreviations
frt = front
rr = rear
rt = right
lt = left
dir = directional
ind = indicator
sw = switch
dk = dark
Bk = Brake
Biggest thing is make sure colors match across the plug halves and make sure no connector is pushed back out of the plastic connector. You did get the red lock strip in place?
I was calling them "lock strips" but I see that FORD called them "sleeve spacers". OK.
ah! Ok, I’ll double check when I pull it apart. I ordered an electrical tester with activator. I have a multi but it’s fiddly to use curled up under the dash.
I did see those flow charts in another post and I thought I went through them thoroughly but I’ll run through them again. Limited time right now to spend on it so I’m trying to maximize my efforts when I do by having a plan.
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