God bless all of you guys on this forum. I am horrible at electrical problems. My F-150 has no lights front nor back. Directionals work as do the brake lights. All of a sudden they went out. Fuses are good Where should I start?

 

"My F-150 has no lights front nor back. Directionals work as do the brake lights."

I am assuming your headlights work too? That leaves the running lights not working(the rear tail, sidemarker, and marker lamps up front)? If so, I would take the headlight switch out.

Check to see if it looks burnt or the plastic is melted on the plug. You will want to narrow in on the tan/white wire and the brown wire. The tan/white wire is the power feed from the fuse box to the marker lamp section of the switch(remember, the headlight switch has several different power sources for each function).

If everything visually looks ok, then I would go buy a test light. Hook one side of the testlight to ground, and then probe the tan/white wire. The tan/white wire should make the testlight light-up. If not, then you have a problem from there back to the fuse box.

If you have power on the tan/white, plug the headlamp switch into the plug, pull the **** to on, and check for voltage on the brown wire. If you don't have voltage on the brown wire, and the plug looked good, then buy a new switch.

If you have voltage on the brown wire, and still no running lamps, then it's going to get fun. The brown wire feeds all over the truck, and finding the problem will take some time.

 

Thank you for your response I appreciate someone helping. I apologize for not explaining that the headlights and tail lights do not work. They are the ones that I am concerned with. The directionals and hazard flashers are the only ones that do work. Also, the dome light went out inside the cab.

 

THe headlights and tail lights work on separate power circuits so my guess it a bad headlamp switch. Also inspect the wiring connector at the headlamp switch as it may very well be melted which will necessitate replacement of the connector.

 

I will thank you.

 

Could not tell if the switch was bad so I replaced it. Still no lights. Where else can I look?

 

Go buy a test light. If you put one side to ground, and stick the probe on a wire with 12 volts, it will light.

See if you have voltage on the black/orange wire. If you do, pull the headlight switch on, and see if you have voltage on the red/yellow. If you do, then check the dimmer switch.

 

Thank you again. I will do that later this afternoon and let you know what happened. Thank you for sticking with me. Dennis.

 

Took the voltmeter, unplugged the front headlight and could not get any reading at the connector. What should I be doing (I may be checking it wrong) to see if there is any power getting to the headlight?

 

If you hooked the black lead of the meter to a good shiny metal place on the front sheetmetal, and then took the red lead and tried each terminal in the plug of the headlight for power with the headlight switch on, then you were doing it right.

If you are not getting power at the headlight, I would check for power at the headlight switch. Use the diagram and description I gave in the above post. The only thing between the headlight switch and the the headlights is the dimmer switch and the wiring.

 

I managed to get out there yesterday and did some testing. Here is what I found:
- At headlight Green, red and black wire - nothing
- High beam foot switch - no power at all three connections.
- at switch - Switch off = black with orange stripe 1.78 volts Switch on = Red with yellow stripe no power
- Fuse box #8 position (Courtesy dome, cargo lamps warning buzzer) no power (key turned on) #4 (exterior lamps, instrument illumination) no power. I noticed only one wire going to the fuse it was light brown with white stripe. Should there be anothewr wire on the other side of the fuse?
- Light green with yellow stripe at fuse box - no power.

 

There is one of your problems. That wire should be hot all the time and have 12 volts on it. Check out at the starter relay and see if you can find a black with orange stripe out in that vicinity. I am going by memory, but I believe there is a fusible link out there that may be bad that feeds that wire. There are a lot of fusible links out on the passenger side inner fender.

 

Thank you I will get out there today. Again thank you for your patience and help.

 

I am about to give up. One more try and it goes to a mechanic. Her is what I got so far. No power to the fuse box. went and checked the fusable links. Here is what's there;

- 3 wires (2 black and one yellow) going to one 14 guage wire
- Green and black coming together to 14 ga link
- 2 blue coming together to 20 ga
- Connector Black, green, red and yellow going into one green to alternator
- Battery wire.

Which link goes to the headlights and tail lights? There is power going to the starter relay. The problem looks like it is between the battery relay and the fuse box. Can I run another wire between the two and if so how do I go about it?

 

If the fusable links are good and you don't measure voltage at the fuse box, the next thing to check are the grounds. Start by measuring the the battery voltage across the battery posts. Leaving the negitive lead of the volt meter on the battery post (not the negitive cable terminal), measure for voltage in the fuse box. If you have battery voltage in the fuse box with the negitive voltmeter lead on the negitive battery post, the fusable links and wiring to the fuse box are OK. If you have no voltage, the problem is probably the fusable link or open wiring. Assuming that you do measure voltage, leave the positive voltmeter test lead where it measures voltage and move the negitive test lead from the negitive battery post to the engine block and then to the body sheet metal. Where the volt reading falls to zero is where the ground is missing or open.

Good Luck.