One Headlight Not Working - Wiring Issue?

Ookami22

New Member
Mar 12, 2017
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Hi all,

First timer here. My gf bought halo/led headlights for her 04 mustang and I wanted to surprise her by putting them in while she's gone for a few days. I prepared the new headlight wiring exactly like the instructional video said. I then went out and disassembled the old headlights...then I tested the headlight connector to see which of the two wires contains power. Unfortunately, because I've never used a voltmeter before, I had it on the wrong setting and when I touched the lead to the connector, it sparked and now the headlight connector doesn't work. The turn signal on the same side does work, but I'm not sure if it's wired into to something else. After putting the voltmeter on the correct setting, I went back and tried to test the connector again. One connection does show a little bit more power than the other, but it's still only at like a 4... Could I have shorted out the connector and not the wires?

I checked the fuses under the hood and near the drivers side panel. None were popped and I replaced the ones that deal with the headlights just to be sure. Still doesn't work. I'm thinking I shorted out the wire and now need to fix it. Does anyone know of an instructional video of how to do it...or seeing as how I got into this mess to begin with, do I need to take it to a mechanic to be fixed?

Thank you in advance for any help you might be able to provide me with!
 
You are aware there are separate fuses for each low beam headlight? Both high beams are on the same circuit. So it's quite possible to have one low beam out and the other not.

So armed with the above information, are BOTH low beams out? Are BOTH high beams out? The exact details could help narrow down where to look.

But. I just don't think it's likely to burn up a fused wire even with a direct short.

I think it's far more likely that:
  • The fuse in the volt-ohm meter is also blown thus giving you a false reading. Test the VOM using a known good voltage (say directly on the battery).
  • You have expanded the pins in the headlight connector by shoving the test leads inside and now they don't make good connection.
  • The fuse is actually blown. Double check your work.
1999-2004 fuse panel schedule:
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271
 
Thank you, wmburns.

I actually fixed this issue earlier. It was a burnt out fuse, thankfully.

Thank you for your help, though!

You are aware there are separate fuses for each low beam headlight? Both high beams are on the same circuit. So it's quite possible to have one low beam out and the other not.

So armed with the above information, are BOTH low beams out? Are BOTH high beams out? The exact details could help narrow down where to look.

But. I just don't think it's likely to burn up a fused wire even with a direct short.

I think it's far more likely that:
  • The fuse in the volt-ohm meter is also blown thus giving you a false reading. Test the VOM using a known good voltage (say directly on the battery).
  • You have expanded the pins in the headlight connector by shoving the test leads inside and now they don't make good connection.
  • The fuse is actually blown. Double check your work.
1999-2004 fuse panel schedule:
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271