It figures that my tail light/signal light is out now that I am planning on getting rid of it. And by "get rid of it" I mean scrap yard

The signal went out. I replaced the bulb and all was well for a couple of weeks. Then it stopped working for a bit. Then it worked for a day and then it was just when ever it felt like it! And now its down for the count!

So the signal/brake light is not working (driver side). 3 wires and not one of them is powered when I have the left signal on. I was hoping it was something easy to figure out and fix. Like a bad ground.
I'm wondering if the black is in fact a ground. If I take the bulb out I should be able to test to ground each wire with an ohm meter. I did test each wire to each other for power and got nothing.

I tried finding a wire diagram without much luck. Found ones that are similar but the wire colours don't match up.

Any ideas out there?
Thanks

 

Check my signature below. So it's 4.6L or 5.4L?

Additionally you said you replaced the bulb so the old bulb blown or not, you tried it on the passenger side?

 

Hi Heiko. It's a 2010 E - 150, 4.9l, 2WD, Auto, Half to find the vin. Ya I replaced the bulb and it worked for a few weeks and then all this trouble. But wait thats not all. The driver side low beam went out tonight! What the hell.

 

Does the LF signal lamp work when selected ?

If I understand your post correctly, you tested for power with the meter set to read ohms, that could blow a fuse in your meter.

When no turn is selected , do both stop lamps work ? yes/no

All these steps are part of isolating just where the problem might be located.
Seems we are dealing with 2 separate problems which very likely are not related.
You cannot always rely on wiring diagrams to be exactly correct. You need to trace what YOU have.

 

Still so many uncertainties and unclear on which bulb is working and not working, need to ask you another 50 questions, you need to tell us the exact working status on ALL exterior bulbs, which I choose not to.
All I can say you have open or short circuit on the driver side.
Open: bulb not blown/burnt, connector or wiring is loose or partially broken
Short: bulb blown, either ground wire is short to power or power wire is short to ground

It's important to determine it's open or short so you know which direction to take, you can do that with a bench test on the bulb. On a 3157 dual filament bulb you need 2 tests. If no open or short is found worst case you can have a bad BCM module and require a replacement and reprogramming.

 

From the diagram submitted ,it appears power comes from the SJB (smart junction box) located in dash fuse panel.
It is not difficult to trace the paths as long as you are familiar with tracing wire colors, PHYSICALLY .

Let us know what tracing you were able to perform, your results and we should be able to offer suggestions for further tracing.
It is a nice challenge, but can be done, just takes a little manual work, lol.
A voltmeter is nice, but to me a simple test light is quicker and easier to see immediately without straining to constantly look at the meter.
There are certain situations where a test lamp may place too much load on components and meter is a better choice, but this is not one of them.


Thank you heiko for the diagrams.

 

I worked over the weekend. Didn't get into the headache!
The left rear signal as well as brake light isn't working. From what I can tell there is no power getting back there at all. I did use a test light. I also have a multi meter clamp on. I did say ohm meter before and see that is miss leading.