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 MGB Technical - USA MGB front side markers not working

Dear all,

I have a '74 MGB from which the both front side markers are not working. For 1 I'm sure that the wiring is not correct (broken line etc.). What would like to know when these should work (I guess when headlight are working, not indicators) and if they haven a relation menaing if one is not working will the other side also be out?

Thanks
Eric
E. van den Berg

Hi Eric.

Take a look at

http://www.mgcars.org.uk/electrical/post__69.html

Do all of the other lights work properly ?.

Don
Don

In my experience, it's almost always a bad ground contact between the bulb and the socket the bulb is inserted into.

Norman
Norman Michaels

The forward and rearward running lights that are
inside the turn signal housings (and the dash guages, and license plate light) should come on
when the headlight switch is at it's first "click"
position (...no headlamps, no side marker lights).

The outboard fender side marker lights, and the headlights, should then come on when the
headlight switch is fully depressed (at the 2nd
"click" position).

Besides having a bad bulb - most lighting
problems can be traced to either a bad ground
(black wire), or a "bullet connector" is corroded
or is broken altogether.

Check all of the connectors in the wire loom that
are located just behind the grill, near the horns.
This area makes the connectors especially
vulnerable to dirt and road spray (winter road salt)
and corrosion. After making things right, it might
be a good idea to apply a bit of silicone dielectric
grease inside the connectors to help keep out any
moisture.

While you're there, you might give all of the other wire loom connectors (near the fuse box) a check,
and take a peek under the dash to see whether if
a wire is disconnected from the light switch.
Daniel Wong

Perhaps this would be the ideal time to remove them and have the holes welded up. They don't enhance the lines of the car much and you wouldn't have to worry about them not working again.
Michael
Michael

When I got my ex usa B the side lights didn't work. The bulbs had corroded in their sockets. I wiggled them about, took them out, sanded them etc and they now work fine.
Peter

The side marker lights should come on when the light switch is switched to the first position. Follow the circuits in the wiring diagrams, Red/green comes from terminal 3 of headlight switch to the fuse box, the red wires from the two top fuses feed the parking, license plate and side marker lamps. One fuse feeds the right lights and the other feeds the left. I have just virified this information on my 74 NA roadster. Good luck Clifton
Clifton Gordon

The operation of the side markers changed in 72. On models without seat-belt warning and before they come on with the headlights i.e. the second position of the main lighting switch - dip or main, after that i.e 72 models with seat-belt warning and after they came on with the parking lights i.e. the first position of the main lighting switch.

I can understand the earlier arrangement failing altogether as all four had their own feed from the main lighting switch, but the later arrangement has each corner connected to the parking light connector that is close by.

Are they light units and not just reflectors? Are there any bulbs in them? What colour is the wiring to them and is it connected?
Paul Hunt

Paul, I guess I was only about half right. Thanks for pointing out the change. Clifton
Clifton Gordon

Clifton - eight-tenths right ;o)
Paul Hunt

Guys,

Thanks for all the help, I'll willl have a look at it.

Thanks
E. van den Berg

This thread was discussed between 06/11/2003 and 14/11/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.