MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Headlamp wiring question

I have a problem with one headlight. It has a properly functioning dipped beam but no full beam. This is not a problem with the bulb (tried new bulb as well as checked new and old bulbs wth my test meter). Evidently there is a break in the power supply to the full beam. I assume that the earth must be OK since the dipped beam is OK.

My question is, looking at the three pin connector that fits on the back of the bulb, am I right in thinking that one socket is power for dipped beam, one for full beam and a common earth? If so, looking at the connector face on, which is which (my guess is power left and right and earth in the centre but which way round are the power sockets). I know I can swith on the lights and identify the power to dipped beam but that still leave uncertainty about the other two.

My guess is that there is a poor connector somewhere but I also want to rule out a broken wire inside the insulation so want to check the integrity of the wiring from one end to the other.

Any help appreciated.

Chris
Chris Hasluck

Trace back the wires to the cluster of connections at the front left side of the radiator as you stand in front of the car. If one side is working, the fault is between the connector there and the light. It will either be a corroded connector or a broken wire or broken connection. if you have a meter to test it will make life much easier.
dominic clancy

A wiring diagram will tell you everything. Black is earth, blue/red dip, blue/white high. Check the bullet connectors on the inner wing front area, i'd guess it's one of those fallen out maybe.
Roadwarrior

I also assumed the centre to be earth when investigating a problem on my MG1300. However, I recall left is main beam, dip is centre and right is earth when the plug is viewed from the front.
D Plumb

If you don't have a test lamp, get one; they're cheap and make life so much easier.
Nick Nakorn

Hi Chris,


Lots get confused by this one!

Everyone assumes the earth is the centre terminal, but it's not.


Viewed from behind, the earth is always the LH terminal, ie the black wire.


The centre pin is dip beam, blue/red



and the right pin is main beam, ie blue/white.



Try that.


Regards Steve.
SR Smith 1

Thanks - that's helpful.
Chris Hasluck

This thread was discussed between 09/09/2014 and 10/09/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.