Hi all,
got an omega 1994 L. Brake light on n/s not working, but bulbs are ok. Tried 2/3 new ones. Is there a particular wire in the multiplug on back of light cluster to check? I think it's the bulb with 2 spots on the bottom.One for tail light, other for braking (correct me if I'm wrong).
I have a digi test meter, but am a bit new to fault finding with wiring.
Any pointers please?
Pete
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1. The fog lamp bulb has one filament and one (positive) contact on the bottom. The brake lamp bulb has two filaments and two (positive) contacts on the bottom. In each case the metal body of the bulb is the negative contact to the car body and back to the negative terminal of the battery.
2. Make sure you are checking the correct bulb in the light cluster. Turn on the lights, then fog lights, then get a friend to put the brake lights on so you are certain what is what.
3. A simple test is to swap the brake bulbs over. If the problem also swaps sides then the problem is the bulb.
4. Set your test meter to DC volts in a range that will measure more than 12 volts. Touch the black (negative) probe to an unpainted part of the car body, or the head of a screw or bolt connected to the body. Touch the red (positive) probe in turn to the contacts in the bottom of the bulb holder. Be careful not to short the contact at the bottom to the side of the holder with your probe. You should get one live contact when just the tail light should be on and two live contacts when both the tail light and the brake light should be on.
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Maybe you can visually trace the metal lines back from the brake bulb holder to the plug?
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Thanks guys,
Armed with your info, I managed to see from the haynes wiring which colour wire was for the brake light. Set the meter to dc 20v & put leads into place then operated brake.....presto. I got c.13.5v constant, only while pedal pushed in. I went to local breakers & got a bulb panel ( & a leather h/brake shroud ) for nowt! and fitted it with same bulbs in. It now works perfectly and I feel better equipped to deal with other simple wiring issues.
I did notice that on the bulb-holder I took out, one of the contacts (where the 2 element bulb goes) seemed less silvery than the other, and it wouldn't clean up. It looked like contact had ' worn ' out.
Thanks again,
Pete
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Another time, if you can't get the right bulb holders and there' a break in the track, consider soldering in a wire link accross the break.
This method is used extensively in the defence electronics industry with PCBs that have cracked tracks.
H
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