Tricky one for the mechanics

[mike rousseau]

So

 

My left turn signal doesn't work at *NIGHT* anymore... Instead if blinking it stays lit...

 

It's a 2005 F-150 FX4

 

Everything works fine during daylight...

 

And if I turn my lights off (dim) after dark everything works fine...

 

My 4 ways also do not blink after dark... But are fine during daylight....

 

I haven't done any work to the truck recently.... It just stopped working at night about 2 weeks ago...

 

 

Any thoughts...???

[ecmilley]

while ford has more than enough electrical issues with REm (rear light modules) and similar devices, i would check rear socket for corrosion and bulb condition the contacts on the 3157 bulbs due fail frequently before giving yourself a brain cramp over it.

Simple stuff first

[Bernie]

I agree with Ernie.
It's possible a filament in a bulb has crossed over to the signal side from the running lights.
Could be front or rear bulb.

[walleyejigger]

i was having all knids of light issues last year with my '06, i ended up tracing it to the fuel pump relay being badly corroded and damagged. the main wiring harness came to a "T" at the relay and from there seperating to ur rear lights. about 230$ part and 1 minute fix. unplug old one, unbolt it, plug in new one and rebolt,

 

on my truck having it placed directly above the spare tire ends up being a perfect place for road salt to accumulate and wreak havoc

 

prolly not ur issue but good to know

[craigdritchie]

Agree, check the simple stuff first. Assuming the truck has auto headlights ..... turn that feature off and turn on full lights manually, as Sinclair suggested. If everything suddenly works fine, then almost certainly a failed ambient light sensor or corrosion somewhere in that system. Very easy to check and either confirm or rule that out.

 

If the problem persists with lights on manually, then I'd check the bulbs on all four corners for corrosion.

Edited March 1, 2013 by Craig_Ritchie

[jedimaster]

could be the harness for your trailer as well, often times they are the root of all things blinker evil

[mike rousseau]

To add more info

 

The cruise also doesn't work at night...

[Bernie]

The cruise likely doesn't work because the brake lamp circuit is being backfed with power through the signal circuit.

Cruise shuts off when brakes applied.
Did you check the bulbs and trailer light plug?

[Muskieman]

same happened to my Expedition, rear brake light bulb, 2$ fix.

[mike rousseau]

The cruise likely doesn't work because the brake lamp circuit is being backfed with power through the signal circuit.

Cruise shuts off when brakes applied.

Did you check the bulbs and trailer light plug?

I'm gunna check mon-tues once I'm done my stretch at work....