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MG MGB Technical - Headlight hassle

Hello all you experts out there. I wonder if anyone could give me any ideas on what is causing my headlight problem. Car in question is stock 1970 MGB (UK specs)
I have one headlight giving me grief..RH side..only glows on high beam nothing on low. Have checked what I thought to be the most obvious, the bulb it seems to be OK. All other lighting and electrics seems fine. Would appreciate any ideas (simple language only please)
Many thanks
Fay
F Cunningham

Probibally the ground. Check the screws that connect the headlight bucket to the car.
John A

As John says, "ground." The high beams have a greater wattage than the lows hence they glow. It's like hooking a 12 volt bulb up to a 6 volt source.

G'day
Blake

Thanks that makes sense as headlight bucket has just ben replaced. Sorry to be so dim but how will I check the ground?? The screws holding bucket to car are all present, new and fitting tightly. Does the ground have anything to do with the two alignment screws?? The problem began when the plastic fastners the screws go into broke.
F Cunningham

Quite a bit onb this in the archives, its fairly common.

First of all identify your headlight cables - they are at front of the car behind grille near the RH horn. Dip and Main both are on separate wires, one is blue with a red stripe, the other is blue with a white stripe.

Recommend you wiggle these, or pull the bullet connectors, clean up and then put back together - the female connection often becoms very weathered and the springy metal becoms brittle losing the connection.

After this: Earth - if its stock spec, chances are the bulb will join up to an earth loom. It will be a black cable joining up to another female bullets, and essentilly runs around the car hooking up most systems. It will be located very close to where you found the blue headlamp connctors. Wiggle claen etc this too and this might solve your probs.

A lot of people disconnect their earth cables for the headlight from the loom, replace it with a heavier guage cable afixing it directly to the body of the car near to the headlamp bowl.

A lot of problems happen in MG because so many systems hook into this earth ring around the car. If there is break in the earth cable or a corroded ppice of wire it can really stuff the electircal function of any component near by. By having separate earth for the important bits i.e. headlights, you lessen the risk of something like this happening again.

~PHIL
Phil

Thanks to all..have pulled and cleaned relevant bullet connections and can now see the light!!
Thanks again
F Cunningham

This thread was discussed on 02/03/2003

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