Electrical help! 03 mustang headlights

Itsjustapigron

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Dec 14, 2018
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So I just installed the “white face reverse glow gauges” and my turn signals work but my headlights (low and high beams) don’t work. Also, I can use the “flash to pass” and my lights come on.. don’t know what to do
 
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wmburns

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Aug 14, 2009
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I give up. What model year Mustang are we dealing with here?

IF we assume this is a 1999-2004 model year, then double check fuses F1.2, F2.38, F2.10, F2.4.

1999-2004 MY fuse panel schedule:
https://www.allfordmustangs.com/for...r-swap-wont-fire-please-help.html#post2669271

Next we have to confirm power out of the the head light switch RD/YE wire with the head lights on. Note, there is a circuit breaker inside the head light switch. Plus the head lights switch does fail after many years of service. Look for evidence of over heating.

Next check the electrical connector to the multi-function switch to be sure it's fully seated.

What to do next depends upon the test results.
 
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Kenestacio

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Aug 2, 2020
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I give up. What model year Mustang are we dealing with here?

IF we assume this is a 1999-2004 model year, then double check fuses F1.2, F2.38, F2.10, F2.4.

1999-2004 MY fuse panel schedule:
https://www.allfordmustangs.com/for...r-swap-wont-fire-please-help.html#post2669271

Next we have to confirm power out of the the head light switch RD/YE wire with the head lights on. Note, there is a circuit breaker inside the head light switch. Plus the head lights switch does fail after many years of service. Look for evidence of over heating.

Next check the electrical connector to the multi-function switch to be sure it's fully seated.

What to do next depends upon the test results.
This was really helpful, thank you. Everything was fine on my ‘03 V6 but the low beams suddenly stopped working. Whipped out the multimeter, no power to the headlight low beam harnesses, but the fuses were all fine, 4 and 10 had power, all grounds fine, no visible breaks or cracks in the wires or main engine harness.

Opened the headlight switch, the switch wiring harness was cracked and burnt around pins B1 and B2 (dark blue/orange, and tan/white), replaced the harness, yay thought I was done—#$%! nope, headlights still dead. Then installed a new switch. Nothing.

Started calling mechanics, got “Nah, we don’t do electrical, call a body shop.” Called body shops, finally was sent to Gus. You know Gus, we all know Gus, he’s a true master. Gus says, “Sure, I’m free Wednesday, bring it on down. $140/hour.” :::record scratch:::

Saw your magical post, wondered what the multifunction switch has to do with the low beams, but opened it up and I had forgotten about that little C202b connector, sure enough, it was throughly toasted. The two red/yellow pins (2 and 3) were falling out the back. A new one is on the way, but meantime I‘ve shoved the pins back in place and voila, the low beams are working fine.

Thanks again.
 
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