I have a 2007 mustang. When I unlock the car with the key fob the low beams come on. I can switch between highs and lows until the lows time out from unlocking. I have checked the fuses and the relays they are all receiving power and the bulbs are not blown. I also switched out the headlight switch hoping that would solve my problem. I’m having a similar problem with the fog lights. If any one can help with some information I’d really appreciate it.

 

So what's the problem. Is it that the lights don't work when the car is on? Or is it that they work when the car is unlocked? Sorry I am a little confused here. When you have the ignition on do you have the lights on as this year doesn't have automatic lights you have to manually turn them on.

 

With the ignition off and keys in my hand when I push unlock on the key fob the low beams come on. Then when I start the car, engine running or just in the on position and turn the low beams on the low beams do not work and the fog lights are not working at all.

 

So if you checked all the fuses and relays and they are all good then you might have a short somewhere. That would be my guess. When you say you replaced the switch do you mean the switch that turns on the headlights or the actual switch behind the steering wheel.

 

the switch that turns in the headlights.

 

so you know that the lights and relays and controls do work, because they work with the unlock and hi/low beam switch; they just aren't working with the normal on/off switch . . . so it has to be something with that switch . . . most likely wiring between the new switch and controller, but I don't know the details . . . since the headlights are actually controlled by the computer, not the physical switch; I wonder if the new switch needs to be programmed to the computer somehow? or it's the same wiring problem that was there before?

 

I would double check that all the fuses are good and relays. Also check the ones in the SJB in the passenger side kick panel. If it's not one of them then it could be a ground issue or a short. That's my best effort. Hope it helps

 

The headlights switch is just a fancy way to connect two wires together so the lights will turn on.
Unplug the connector and hotwire the two that are needed to turn on the headlights with a wire.
Take a look here:
https://iihs.net/fsm/?d=40&f=Headlam...olamps.pdf&p=2

The Red-white and Yellow-light blue (ground) turn on the headlights. Hotwire these two together with an extra wire and see if they turn on. If they do then it's the switch. If not then it's something else.