Hi all 

My wife's got a 2012 mk7 fiesta 61 plate. Headlights have been intermittently failing and are now complete dead. Side lights and high beam are fine. But dipped beam complete unresponsive. 

 

I've checked fuses and bulbs obviously. No power to fuses, relay isn't turning on. Swapped relay. Still no good. Relay has two live feeds, a ground and I thin brown and blue wire that I assume routes back to bcm. I can't get any signal from this wire? Not sure if it's a switch live or switch ground. 

I've tried different bcm. I've check input parameters from headlight switch and light sensor and they're all good. Now I'm at a total loss! 

Can anyone confirm what signal I'm suppose to have from bcm to the relay? Or does anyone have any idea what wire from the bcm feeds the headlights? Any help would be greatly appreciated 

Hi Daniel, are you good at reading wiring schematics ? Is your Fiesta the Mk7 with Auto Headlights ?

The low beam (dipped beam) is directly controlled by the BCM, there are no fuses and no relays involved.

You can download the full Ford schematic direct from my Google drive:

https://drive.google.com/file/d/1mx9V35csu2w81lReFOrbMaa9_5rllDt1/view?usp=sharing

Thanks for your response. I've traced most of the wiring, the dipped beam does have a fuse for either side, then to a relay, the relay is switched by a switched ground which is fed by a brown and blue wire from the bcm. For some reason the bcm isnt sending a switched ground. Could this be due to a bad ground somewhere? I'm not sure. I'm at bit stuck now. Car does have auto lights 

2 hours ago, Dan_B said:

the dipped beam does have a fuse for either side, then to a relay, the relay is switched by a switched ground

Hi Daniel, can I ask what the fuse numbers are, and which relay you have for the dipped beam ?

Fuses 12 and 13 as listed in the owners manual, and relay 5. Looking inside the fuse box, the feed to fuses 12 and 13 come from the switched live output of relay 5. Relay 5 is getting two lives in but no switched ground in order to make the relay click. 

 

This is on a UK mk7 vehicle last of the 2008-2012 shape. 

21 minutes ago, Dan_B said:

Fuses 12 and 13 as listed in the owners manual, and relay 5. Looking inside the fuse box, the feed to fuses 12 and 13 come from the switched live output of relay 5. Relay 5 is getting two lives in but no switched ground in order to make the relay click. 

Hi Daniel, those fuses and the relay are for the Main Beam only. As I said the Low Beam (Dipped Beam) does not have any fuses or relays, it is controlled directly from the Body Control Module. Please see attached schematics.

Sorry my mistake, fuses 14 and 15. 

I appreciate your help, but I'm not sure the fusebox, relays and lighting circuit are the same in the UK as the one you're looking at. 

The dipped beam on this vehicle definitely have a relay feeding them and two fusses.

I'm in the UK (Co. Durham) and the Ford wiring schematics are for a UK/European 2012 Mk7 Fiesta RHD.

Are you not is the UK ? your profile says Leicestershire.

Fuses 14 and 15 both in the Engine compartment fuse box and also in the passenger compartment fuse box are not for the Dipped beam lights.

 

 

Yes, as per my profile, I'm in Leicestershire. I don't really know what to say, the fuse box layout is as per the owners manual and one or two others I've seen online. I can confirm this is correct for my car; if I plug the relay in, with its cap removed, and manually operate the magnetic arm, the two fuses I've mentioned are powered up and the headlights come on. 

What I'm not getting is a negative switch feed to the relay from the bcm to turn the relay on. 

The car seems to experiencing an earth issue at the moment too. Difficulty starting but perfect with a jump lead from battery to body. Flcikering interior lights until I put a jump lead across. Do you think this could be the issue? Odd that it only seems to affect the dipped beam and everything else functions OK. 

 

Again, appreciate your help. Sorry our car seems to be different from your data. Maybe because its a late reg mk7. By year it should be a mk7.5 but it is a preface lift mk7

Just for anyone else suffering with the same issue. I did resolve this. As above, the relay what feeds the dipped beam headlights wasn't getting a switched ground from the body control module, thus the relay wasn't turning on. This was down to a broken wire, inside the engine fuse box caused by corrosion. New wire ran and headlights back working. 

If and when tracing a broken wire or high resistance joint do use a test lamp. Multimeteres will often show voltage but  needing virtually no power, whereas the light needs a little power also  so giving a more accurate result.

On 2/26/2023 at 10:26 AM, Dan_B said:

Just for anyone else suffering with the same issue. I did resolve this. As above, the relay what feeds the dipped beam headlights wasn't getting a switched ground from the body control module, thus the relay wasn't turning on. This was down to a broken wire, inside the engine fuse box caused by corrosion. New wire ran and headlights back working. 

Hi Dan, my son has the same issue with his fiesta Mk7, was it an easy fix? He is pretty good with fixings things or do you think it's an auto electrician job, I'm 150miles away so can't help him,

Thanks in advance, 

Chris 

6 hours ago, chris Hodge said:

Hi Dan, my son has the same issue with his fiesta Mk7, was it an easy fix?