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Headlights low/high not working

Hi I have daewoo lacetti 2004 sx,

suddenly the headlights both high/low had stop working.

I had check the fuse, relay and in car switch everything is okay. When I turn the switch once I hear the position (illumination) lights relay click, then turning the switch once again to turn on normal lights, second relay also clicks (H/L lights relay) , but lights are off. The bulbs are also okay I had checked them manually… currently only position/illumination lights are working and I can use high lights when blinding.

I also unplug the connector from the lights (6 pin conn.) and took volt metter to check the current, something is strange since pins 1,3,4,5,6 are acting as ground while on pin 2 I can measure 12v. When I make any combination between pins 1-6 excl. pin 2 I get 0v.

Went to electrician he did almost the same stuff and said that maybe is the car switch or maybe car is missing - minus.

Another important information is that current car wiring is having B+ on all fuses meaning that components are charged with 12v always just - is switched.

Can someone please tell me some workaround like how to wire the lights directly on 6 pin connector to have them working until I have problem solved properly, or if someone have any idea what can be the cause of the problem would be great to share it.


You will see 0 volts on any connection that doesn’t have current flow through it, is tied directly to ground, or has no connection to power. If pin 2 of the switch you refer to supplies the power to the other connections of the switch and the voltage on that pin drops to zero when things are connected and making a connection then that would mean there is a bad connection to power on the wire going to pin 2.

You seemed to indicate that the headlights work with the flash mode. If that is correct then the trouble would seem to be with that switch connection while it is in the normal mode.

I would partially disconnect the connector going to the lamp bulb so you expose the terminals but so they are still connected to the lamp.

There should be three conductors- Low filament, High filament and common.

Put your meter black lead onto a chassis ground location.

Put the meter red wire on the positive battery terminal. Verify you read 12 volts or thereabouts. This proves you have a valid ground point.

Now turn on low beams. Poke meter red lead into each of the bulb terminals one at a time. One should read 12 volts, the other two zero. If none read 12 volts, you have a supply issue. If more than one reads 12 volts you have a ground issue.

Good advice by TT above, check for the proper voltage at the bulbs. No bulb will light if it has no voltage. And any good bulb will light if it does have proper voltage to it. A bulb may have more than one filament, , but only two pins are involved in lighting one filament. Battery voltage on one, and chassis ground on the other will always light up a good bulb. That’s where to start, use a volt meter to measure the voltages at those two pins. Experiences diy’ers would have access to the car’s wiring diagram, that makes this kind of test much easier. If you want to diy, suggest first thing to do is get access to the wiring diagrams.

Hi TwinTurbo,

Thanks on the advice, actually I did what you had suggested… maybe I wasn’t clear enough.

The pins I had mention are on the bulb connector. It has 6 pin pins on each bulb connector where 2nd pin has current all the time, while all other pins are 0v no metter of the switch state (high/low). I also tried to have black wire from the multimer on the chassis and red wire on any pin of the connector I get no power at all.

Hope it is more clear…

While for wiring diagram I’m unable to find any of them.


If pin 2 of the switch has power on it at all times and no voltage is getting to any of the other pins of the switch, at any switch position, it would seem you have a bad switch.

You see 12 volts when probing between terminals at the connector but see no terminals with 12 volts when you have meter black on chassis ground? Did you try putting your red meter lead to the battery to confirm you read 12 volts? Again, this will prove you have a valid ground. Its important step because further diagnosis depends on that answer…

Problem solved, the wire for ground was “broken” : between fusebox and the lights.

1 Like

Fantastic! Glad to hear you found the problem and thanks for posting followup!