Both low and high beam headlights not working

[ATCzMustang]

I have an interesting but somewhat serious issue on my 01' Cobra. I've already investigated the parts involved and they are the same as V6 and GT so doesn't seem to be a Cobra specific issue here.

My low and high beam headlights will not work when turned on. :uh oh: The rear lights, turn signals, and fog lamps all still work properly.

The other important thing to note is if I flash my high beams from the turn signal lever on the steering column they do work, and the high beams flash.

I have checked all the fuses they are in tact. I also replaced one of the headlight bulbs just in case there was some surge and they both blew out, but the bulbs are not the issue.

I've read a bunch on the internet and the main components are the headlight bulbs, the fuses, dimmer on/off switch, and the 'multi-function turn signal switch' which is the turn signal lever on the steering wheel column that has 2 harnesses going into it. There are apparently no relays for the headlamps on this year and all of the work is done from the multi-function switch.

Anyone have experience with this or have any idea what would cause both the high and low beams to go out but everything else works? I want to fix it myself and save if possible.

 

[ATCzMustang]

Well... the problem is fixed but I went the long way about it and hopefully I can save someone some $$ in the future by the result.

I bought the multi function switch from Ford and installed it myself. I could have saved a few $$ on eBay but I needed the part quickly, so it came out to $113 after tax. I installed it and it did not fix the problem. :shrug: By the way this is a FANTASTIC tutorial on how to change the multi function switch: http://www.sn95forums.com/showthread.php?47224-How-to-replace-you-Multi-Function-Switch

I took everything else involved apart or at least inspected including the following:

1. Inside Fuses
2. Outside Fuses
3. Bulbs
4. Wiring Harnesses
5. Dimmer / Headlight Switch

Everything from the outside looked good.

The last part in the entire electrical schematic that I had not yet replaced was the dimmer / headlight switch. I vsually inspected it and I assumed it was working because other lights would come on and the dimmer worked. I contemplated going to the Ford parts window and buying that part too for $45 and putting it on as 1 last attempt before taking to service.

I did not do this as I didn't want to throw more $$ at parts that were not fixing the issue. I already wasted $113 on the multi function switch. Therefore I took it to service.

Murphy's Law at it's best and it was the dimmer / headlamp switch. :cuss:

So the out the door bill was $130 for that after diagnostics + parts. So all in I spent around $240 for a part if I ordered off the internet is about $35.

So if anyone has both high and low beams go out on their Mustang, it might be the headlight switch. I'll post the part number later - have to get the receipt.