headlight wiring problem

Josh79

New Member
Sep 7, 2005
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South Dakota
My low beams do not work. Highs work fine and so do flash 2 pass. I replaced the plug/harness last year because it was melted (common thing i found out) and they have been fine since then. They stopped working a week ago. I 1st tried a new multifunction switch but that didnt fix it then i tried a headlight switch and that didnt either. I had it all tore apart and i had my hand back in the dash where all the wires were and i got them to come on for a second then i pulled my hand out and they went off and i tried it again and they came back on. but now i cant get it to do it again.

I took the cluster out and i can see all the wires as far back as possible and the red w/ yellow strip wire has power as far as i can reach back to test it and none of the wires are melted or broken. This is the wire that runs to the headlights right? Because it has no power when the switch is off but turn it on and it has power. All the bulbs are good and so are the fuses. Any ideas? Where does the wire split to the two headlights or go through the firewall so i can test it there. Any help is appreciated. Thanks
 
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By your description you have a bad connection. I had a identical problem on another vehicle (lead from the multifuntion switch harness) that had pulled loose from the harness but visually looked okay. (Stressed from the tilt function). It wasn't until I pulled on the lead that I realized that the wire had come free from the crimped connector in the harness.
 
Red/yellow is the output feed from the headlight switch to the MF switch. If it's bad, you will lose normal high and normal low beams, but your FTP still works because it sources power elsewhere.

Lt Grn/blk and Red/blk are the individual feed wires for high and low.

I agree with Toyman about the symptoms. The red/yellow wire is famous for backing out of MF switches and even burning up sometimes.

Really check it over on both ends - you will probably find your issue at one end or the other.
Also really inpsect the headlight connector (that is part of the body harness). They burn up occasionally.

Good luck.
 
The regular high beams still work also not just ftp. The red/yellow has power @ the headlight switch and as far back from the headlight as i can reach in the dash. So if it is the feed from the mf switch than that means i am getting power at the headlight switch correct and that wire is fine? So i need to look into the light green/black or the red/black for the low feed because one of them is the wire that runs from the back of the headlight switch to the low beams (i think right?).

I just replaced the headlight connector at the back of the switch last year so that should be ok. I remember when i replaced the connector and there was 2 extra wires, i assumed it was normal because they have worked fine ever since. I did notice that one does have power but it is taped off so it shouldnt have shorted anything off. I am sure that wiring is fine as it has worked for a year so everything should be in the right place.

Tonight ill look into those 2 wires and check the mf connections. Any other suggestions? I hope i get it fixed im tired of not driving it :notnice:
 
This is an interesting one. Here's what I'm seeing:
Your red/yellow should be ok, otherwise you would not have natural high beams.

Your high beam output wire from the MF switch is fine.

Your low beam output wire should be fine because you have noted you have flash to pass. Now, to clarify, flash to pass illuminates both the low and high beams simultaneously. If yours works as it should, that means your low beam wire egressing the MF switch is fine and that it sounds like a MF switch issue.

But if FTP actually is only putting your high beams on (no low beams), then as you noted, jump all over that low beam wire. And no, this does not leave the headlight switch.

Here's what happens: The headlight switch is just that, a switch. The MF switch is the high and low beam splitter. The headlight switch (with regard to headlights) just powers red/yellow or it doesnt. It's the MF switch that takes this feed and divvies it up for the low or high beam.

This is why I think you gotta get access to the MF switch connector. Try to wiggle wires to see if you can make the lights cut out again, and track down what is moving. I once had a wire back out of the MF switch just a hair. I couldnt even see it but found it with a wiggle test (once wiggled, I could see the wire move more than the others, since it wasn't anchored properly at the connector. It was kind of a similar thing to what Toyman had).

Good luck.
 
ok im about ready to push it off a cliff.

Well when i ftp the lows dont come on (used a test light in headlight plug to find this out). so naturally i figure it has to be the red/black wire (low beam correct?) loose/shorting out somewhere.Well i wiggle bend flex etc and i cant get nothing i have moved every inch of the wire i can reach and nothing. So i pulled the plugs for the mf switch to below the dash so i have better access and i took off all the tape so i can see all the wires and they all look fine. The wires have some play in them at the back of the harness but i cannot make the lights come on by pushing them in, wiggling etc. Can i get this short harness at ford? (and is it going to cost an arm and a leg. i am totally stumped. I have power @ the back of the harness of the red/black wire so it should be feeding juice to the lows.

Now my only thought is that it is broken in the firewall or atleast further down stream than the mf harness. Where does it go through the firewall? I didnt look tonight because i am just tired of it so ill mess with it more tomorrow night.

I dunno if maybe i was halucinating when i thought they came on earlier or what. And when i thought they came on i was wigging the wires that came out of the headlight switch back behind the dash but i cant get it to happen again. So maybe it was something else that caused them to come on and i just didnt realize it.

Also i had a thought. I would take the red/black (low beam) and the green/black (high beam) wires and switch them at the back of the harness. So i cut and respliced them so now lights are on when i turn the "lows" on but they are still brights. It didnt change the lights that came on just when they come on. Any other ideas to get me low beams now instead of highs??
 
I'd have to check but I believe you're right about red/blk being for lows. That rings a bell.

So the red/blk wire has 12 volts at the MF switch (to confirm)? If so I like your intermittantly open-wire theory. If it was me, I'd run a new wire for now. You could add a relay on the low beams if you like as well.

On a fox III, the headlight feed (and high and fogs) run down the driver-side body harness under the hood. I assume ours is the same since the MF switch and underhood fusebox is on that side.

Good luck.
 
ya i think that i am just gonna run a new wire from the back of the switch to under the hood. I wonder if it is shorting out near the firewall. hard to tell. HOPEFULLY get it so i can drive it tonight
 
well i fixed it last weekend. The wire must have been broken/shorting out in the firewall or something. I ran a new wire from the mf switch to up by the battery and it works fine. Tried to pull out the old wire to inspect but it wasnt budging with all those wires and i didnt want to mess something else up. I managed to pinch the new wire when i tightened up the steering column but luckily i caught it. When i first started messing with it i did something to kill the ftp so now ftp doesnt work but it doesnt matter everything else is fine.