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Discussion Starter #1
Ok well first off, I just bought my FIRST mustang yesterday! its an 2004 40th anniversary edition v8! So i'm very new to these cars so pardon me if my inexperience shows through! :D

I've tried searching for this problem on the forums and really didn't get a good answer so i'll just ask.

The low beams and parking lights work, i try to turn on the high beams and nothing! Flashing them doesn't work either and nor do i get the blue high beam light in the console when i attempt either. I replaced the bulbs and that didn't fix it. It doesnt have an owners manual i tried looking at a fuse diagram on the internet but it doesn't say anything about high beams in the descriptions. what fuse number should i be looking for specifically? If its not the fuse though, what are some other solutions?

Thanks in advance! :cool:
 

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I'm not familiar with the electronics on that particular vehicle, but I assume there is a relay to control the highbeams in the fusebox. That is the first thing I would check and it can be checked easily if there is another relay under the hood with the same part number that you know is good, (fuel pump, horn maybe?) Then you can swap them and see if your highbeams work.

P.S.
Welcome to MM
 

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and there is a fuse under the hood but its only for both the headlamps,you shouldnt have to replace that one since you low beams are working
 

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Discussion Starter #6
Lol ok, well the fuse was blown, replaced it. I can flash the high beams now but when i switch to the high beams they still won't come on. Pretty crazy!
 

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Are you pulling the switch towards you or away from you? You have to push it away from you to get them to stay on. When I bought my stang it took me like 2 days to figure that out.
 

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You can download the Owner's Manual from Ford, click here.

Here's the schematic for the headlamps. The problem has got to be in the multi-function switch, contact #14 on the "right-hand" pole of the switch, as all the wiring and fuses are shared.



For "flash-to-pass" contact #15 closes on both poles of the switch and activates both low and high beams--for high beam contact #14 on th right-hand pole closes, passes power to contact #15 of the left-hand pole, and turns on the high beams.

The dash indicator is powered in parallel with the high beam power after fuse 2.38.
 

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Discussion Starter #12
You can download the Owner's Manual from Ford, click here.

Here's the schematic for the headlamps. The problem has got to be in the multi-function switch, contact #14 on the "right-hand" pole of the switch, as all the wiring and fuses are shared.



For "flash-to-pass" contact #15 closes on both poles of the switch and activates both low and high beams--for high beam contact #14 on th right-hand pole closes, passes power to contact #15 of the left-hand pole, and turns on the high beams.

The dash indicator is powered in parallel with the high beam power after fuse 2.38.



So is there any way to test to see if its the multi-function switch or should i just go ahead order one online and replace it?
 

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Sure,

Check the voltage at fuse 2.38 when the switch lever is pushed forward (high beams) if there is no voltage (there won't be, if there were the high beams would be on) then the switch is bad.

Also, note that unlike most foreign cars there is no headlamp relay. This is legacy US car design where the headlamp switches handle the full current drawn by the lights--in this case 12A steady state with bit more inrush current.

This is not an insignificant amperage and I'd bet if you open up the MF switch¹ you'll find some pretty crappy contacts being used to switch that load.

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¹ - "MF" as in Multi-Function switch, though I suspect at this point you might interpret the "MF" part otherwise.
 

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Discussion Starter #14
Sure,

Check the voltage at fuse 2.38 when the switch lever is pushed forward (high beams) if there is no voltage (there won't be, if there were the high beams would be on) then the switch is bad.

Also, note that unlike most foreign cars there is no headlamp relay. This is legacy US car design where the headlamp switches handle the full current drawn by the lights--in this case 12A steady state with bit more inrush current.

This is not an insignificant amperage and I'd bet if you open up the MF switch¹ you'll find some pretty crappy contacts being used to switch that load.

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¹ - "MF" as in Multi-Function switch, though I suspect at this point you might interpret the "MF" part otherwise.


Thanks! I'll try that out later when i get the chance and let you know the results.
 
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