Issues with 2003 Ford Focus headlights

Question

The problems started when we found out that my car had no dim lights even though the bulbs and fuses seemed to be perfectly fine, and so were my brights. So the mechanic somehow "jumped" my dim lights through my brights and managed to get both working. We discovered a few days ago that my passenger light was out, and upon looking at it found that the wiring shorted and actually melted parts of my headlight assembly. The lights on the driver side (dim and bright) both still work fine. From what I'm reading online it sounds like it could be an issue with a relay, but my knowledge of cars is extremely basic.

Could someone please tell me if this sounds like a relay or if it is more likely to be something else?

Answer 1

This might not be an answer but rather a suggestion. I'll explain a few things since you say you have limited knowledge of vehicles.

Jumping a circuit is never something you should do. Dims and High beams are two different amperages. They both run on 12v, but the actual amount of power is different. When you "Jump" a circuit and combine them like that, you're not only mixing amperage, but you're also doubling the load of that circuit. Eventually the wires, relays, or fuses will be overloaded and something is going to break. If you're mechanic doesn't have a wiring diagram in front of him, he has no idea how the circuit works and what he should be fixing. If they are computer controlled you run the risk of damaging the ECU/ECM. To me this sounds like you you have a short in the circuit somewhere. The easiest way you could track this down would be to get a multimeter and test for continuity between the lights and steering column. You'll have to then find out WHAT exactly is causing the issue. Those relays aren't cheap and unless you have a good deal of electrical knowledge they're difficult to test.

Iwould highly suggest taking it to a electrical shop or the dealership, because they'll charge you $90 for diagnosis and you can fix it yourself once they tell you what it is. If you want to be adventerous you can try and track it down yourself. www.eautorepair.com has wiring diagrams and it dosen't take too long to figure out how to read them. Lots of hardware stores sell test lights and multimeters as well.

Good luck.

Answer 2

This is really quite straightforward. You had a wire going from your high beam's + lead to your low beam's + lead. Somewhere along that run of wire, it shorted to ground (touched the frame likely, assuming your ground wire isn't also burnt).

Bypassing a wire isn't necessarily a bad last resort. However, it should involve running a new length of [appropriate gauge] wire from the fuse box, through the firewall, to the headlight. In that manner, you're not overloading some other circuit.

Take it to a mechanic and have them sort it out if you're not handy with electrical work. The original problem (pre-wire jump) will have to be resolved and reconnected (or) the jumping wire run replaced correctly.

Answer 3

I'm surprised the fuse didn't blow, if there was enough power going through the cables to melt it. :)

You can quickly test the relay with a voltmeter and some alligator cables.

1. Remove the relay
2. Give the relay a small shake. It should feel and sound solid with nothing rattling inside.
3. Use a voltmeter to ensure that there is no connectivity between the switched terminals (usually numbered 87 & 30).
4. Apply 12V power to the relay coil (+12V on pin 86, ground to 85... although I don't think the direction actually matters). The coil is what produces the magnetic field that physically brings contact between the switched pins.
5. Use a voltmeter to ensure there is connectivity (with near zero resistance) between the switched pins (87 & 30).

If it's not the relay causing the problem, carefully inspect the cables going from the switch, relay/fuse box, main harness, and to the headlight assembly. It sounds like the issue is caused by too much current to pass through the cable, above the rated current, overloading the circuit and melting the insulation.

Once you get the shorted/melted wires sorted out, use an ammeter to ensure that the headlights are drawing a proper amount of current that is within spec of the cables, fuse, relay, and bulbs.