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Hi, Bought my daughter a three year old Fiesta SE (2011) when she graduated from college - to make sure she had the means of leaving the nest! Recently she called to say that her headlights did not always turn on when she turns them on - this car does not have Daylight Running Lights - she has to turn a switch on the dash. I traded her cars and experienced the same thing - 99% of the time the headlights come on - but occasionally they do not. The brights worked. The various other amber lights all worked - but not the headlights. I don't know what to change to fix this. Seems like it cannot be a fuse or it wouldn't work 99% of the time. Same with Bulbs. Wondered about the actual switch itself - but it seems unlikely. What else might make this happen occasionally? Thanks for any insights. People at various AutoZones, O"Reilly's, etc did not seem to know - in fact, one of them suggested this forum.
 

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Hi Greg. Happy New Year. Hope it will be healthy and enjoyable for you.
I tried to attach a photo - read the FAQ and lots of posts from people with the same question - and I'm stuck. My profile says I may NOT post attachments - so for now there is no photo.

I opened the fuse box and was surprised at how dirty it was inside. There is a layer of gritty dirt which is stuck to everything. You have to scrape it off - it won't blow off. I pulled out one of the headlight fuses - and the two metal strips have some corrosion on them. Like an oxidized layer that I can scrap off with a knife. Reminds me of a car battery terminal.

Do you think this could cause my headlight issue? What would you suggest to correct it - removing and cleaning each fuse?

Have you heard of this particular headlight issue before? I didn't find a similar thread in the forum - but there are so many threads that I may have missed it.

Thanks for any insights.
 

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Discussion Starter #4
Just Hit various fuses and fuse box with Electronic Parts Cleaner

Stopped at Auto-Zone and they suggested Electronic Parts Cleaner for fuse box. So I hit it with that. I scratched up the fuse surfaces with my knife earlier today. So far so good.
 

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Discussion Starter #5
Headlights still not fixed

Ok - I cleaned up the fuse box - hit it with electronic cleaner too - and yesterday my daughter informed me that her headlights did not work that evening. So they worked perfectly fine for 9 days - and then wouldn't turn on.

Is replacing the actual switch the next step? It's going to be so hard to get under the dash of a Fiesta to work. Sigh.
 

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Discussion Starter #7
Brights = High beams. They have always worked. But the main beams (what I referred to as headlights) only seem to work 99% of the time. Which means my daughter has to occasionally drive home with her brights on - as the main beams did not turn on when she turned the headlight switch. She does not have daytime running lights - she has to rotate a switch on the dash.

Does this car have headlight relays? The fuses all seem good and I cleaned them. Wondering about replacing the switch itself - but I can't think it has gone bad. Hope it's not a short circuit in a wire somewhere - no idea how I would find it.
 

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Brights = High beams. They have always worked. But the main beams (what I referred to as headlights) only seem to work 99% of the time. Which means my daughter has to occasionally drive home with her brights on - as the main beams did not turn on when she turned the headlight switch. She does not have daytime running lights - she has to rotate a switch on the dash.

Does this car have headlight relays? The fuses all seem good and I cleaned them. Wondering about replacing the switch itself - but I can't think it has gone bad. Hope it's not a short circuit in a wire somewhere - no idea how I would find it.
 

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Discussion Starter #9
Brights = High beams. They have always worked. But the main beams (what I referred to as headlights) only seem to work 99% of the time. Which means my daughter has to occasionally drive home with her brights on - as the main beams did not turn on when she turned the headlight switch. She does not have daytime running lights - she has to rotate a switch on the dash.

Does this car have headlight relays? The fuses all seem good and I cleaned them. Wondering about replacing the switch itself - but I can't think it has gone bad. Hope it's not a short circuit in a wire somewhere - no idea how I would find it.
 

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Brights = High beams. They have always worked. But the main beams (what I referred to as headlights) only seem to work 99% of the time. Which means my daughter has to occasionally drive home with her brights on - as the main beams did not turn on when she turned the headlight switch. She does not have daytime running lights - she has to rotate a switch on the dash.

Does this car have headlight relays? The fuses all seem good and I cleaned them. Wondering about replacing the switch itself - but I can't think it has gone bad. Hope it's not a short circuit in a wire somewhere - no idea how I would find it.
The headlights are powered by the BCM. The headlight switch is a simple hall effect switch that sends a 5v signal to the BCM to tell it to turn on the headlights. Same for the high beams, your multifunction switch sends a 5v signal to the BCM to tell it to turn on. The BCM has internal relays and circuit breakers to protect itself from short or overload. The circuits are also fused out of the BCM.

One would need to do a pinpoint test of the input/outputs of the bcm when the headlights were failing to turn on. You could do this with a set of backprobe needles and a DMM. I can send you the pinpoint test procedure out of the FSM if you think it's something you can tackle.
 

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Discussion Starter #11
Brights = High beams. They have always worked. But the main beams (what I referred to as headlights) only seem to work 99% of the time. Which means my daughter has to occasionally drive home with her brights on - as the main beams did not turn on when she turned the headlight switch. She does not have daytime running lights - she has to rotate a switch on the dash.

Does this car have headlight relays? The fuses all seem good and I cleaned them. Wondering about replacing the switch itself - but I can't think it has gone bad. Hope it's not a short circuit in a wire somewhere - no idea how I would find it.
 

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Check for corrosion on the engine fuse box. Front most, left (closest to the engine) pull the relay and take a look at the connections. If it's bad the connectors on the relay may break off as you pull it out!
 
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