Signals are not working - 2003 Ford Expedition

There are a few possible reasons why your turn signal light is not working while your brake and tail lights are functioning properly:

1. Blown fuse: The turn signal lights are connected to a different fuse than the brake and tail lights. The fuse for the turn signals may have blown and needs to be replaced.
2. Turn signal switch: The turn signal switch, located on the steering column, could be malfunctioning and needs to be replaced.
3. Wiring issue: A wiring issue, such as a broken wire or loose connection, could be preventing power from reaching the turn signal lights.
4. Flasher relay: The flasher relay is responsible for controlling the turn signal lights. A faulty flasher relay could be preventing the turn signals from working.
5. Signal/light module: Some cars have a signal/light module that controls the turn signals, this could be faulty and need to be replaced.

In the diagram for rear lamp, the top wires are voltage, the bottom black wire is ground. The brown wire on either side should be tail lamps, goes hot when you turn on the headlamp switch. The other top wire on either should be for turn signal. With everything turned on, is there voltage on that wire?
Because the front works and the rear don't, possible wiring circuit problem? The voltage for turn signals comes from bcm. The bcm knows when you turn on turn signal switch, either side, then the bcm sends voltage to turn signal lamp at the rear and front.

try the hazard lights. if they work check the bulbs with them working. if good and the turn signals not working then it could be the signal flasher is bad. witch out the hazard flasher for the signal flasher it they work then replace flasher, or the turn signal switch it bad.

either wrong signal bulb or short in left turn signal wiring if both left signal lamps not working.if only one of left turn signal dont work could have corroded bulb socket spray a little electronic cleaner in bulb sockets see if left signal work.

Replace the turn signal switch. Bad contact inside causing a crossing of the circuits. When the turn signal is applied it should open the brake light circuit allowing for just the signal to work. Doesn't sound like the switch is doing it's job.

most likely its the turn signal relay. which is under the hood. in the fuse box. also make sure ur running lights are working if they are connected to the turn signal.

When your turn signal goes out it tends to blink VERY rapidly before burning out, It's a nice way to let you know before hand that you need to replace the bulb soon.

The only thing that should not be working would be the audible turn signal / hazard signal sound. When the turn signals are activated, the audio (radio) system generates a clicking sound that indicates the signals are working.
When the radio is missing, no sound is generated.
Are your turn signals working outside, but no sound or are the signals not working at all.
Let me know.
Regards,

replaced turn signal flashers and muti switch turn signal still won't work Why?

Now replace the flasher unit! Frankster016