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MG MGA - side light woe

Help, i have lost my side lights and also my number plate light, i have recently removed and refitted the number plate light so i would not be suprised if it was something that i have done but not being electrcaly minded i could do with a little help,ie could i have caused a short or lost an earth ect any help would be much appreciated, thank you,
Vin
Vin Rafter

Vin
I would have thought that you have just disturbed the earth cable. Try temporalily earthing it with a piece of wire and see what happens.
I haven't checked on my car but according to Barneys diagram there appears to be a bullet joint that may just have worked loose.
http://mgaguru.com/mgtech/electric/circ_d.htm
Graham M V

Vin, I would think the wires have come off the S1 terminal of your lighting switch. Do your panel lights work?
Lindsay Sampford

Parking lights at all four corners and the license light and the dash lights and the map light when switched on all run on the same circuit (all red wires). Do any of these lights work?
Barney Gaylord

Be careful with this. A short at that light was the cause of a wiring burn out in my car 10 years ago. Remember there is no fuse in the lights

If you have touched nothing else would suggest you have connected the light terminals the wrong way round, so your lighting is going straight to earth. Your have been lucky of you have not melted the wiring yet.

Otherwise, do the other rear lights work? If they do, then check that the wiring connectors behind the right rear wheel is still all connected. This is the only place that the licence plate light becomes independent of the others
dominic clancy

I have have found that the light switch has a fuse holder (see photo) so i think it must be incorrect but it works, it had in it a 35 amp fuse witch was blown so i replaced it and the front side lights and map light worked but not the rear and the fuse got really hot before i removed it, does this indicate that i have a short somewhere and if so can anyone tell me how to go about finding it thank you again, Vin


Vin Rafter

It is staggering to me that people would rather have a concours car than a safe protected vehicle. The various circuits on the MGA should be fused and sod concours otherwise you run the risk of burning your car out or having difficulty finding various faults Installing a fuse box and seperating and fusing all circuits is a major benefit.

Your car sounds like a temporary fuse installed has saved it from being burnt out and lost.

However Vin now you need to trace the fault by disconnect the wire that is causing the problem and tracing it to fine where the short is. This can be done using a meter or with reference to the wiring diagram (MGA is extremely simple especially the 1600) then follow it and find the short.
Robert (Bob) Midget Turbo

Here is the fusebox I fitted to my car when I rebuilt it about 10 years ago


Robert (Bob) Midget Turbo

As I said before, if you have ONLY replaced the light, you have probably connected the wrong way round, or the power connection is shorting to earth.

Disconnect the cables from the new light and see what the result is.
dominic clancy

Sorry missed the number plate light story was too busy moaning about concours cars.

Simply reversing the connections (assuming it has 2 wires) on the numberplate light would cause this very problem. As Dominic suggested.
Robert (Bob) Midget Turbo

Sorry to come in so late on this thread Vin, just got back from Spain and spotted it.
If you havent already fixed it, heres my 2 penneth.

Sounds like a dead short somewhere Vin, probably the lighting circuit at the rear of the car.

The red wires are the live feeds from the switch and the black wires from the light units are the earth wires (usually)
Im so glad you have a fuse in the circuit as otherwise you would definitely have had a wiring meltdown or even a fire by now otherwise.

You can check the circuits with a meter but before you try the lights again I would temporarily fit either a small 12 volt battery or maybe a low power battery charger instead of the cars own battery.
Then if there is still a short circuit, you wont cause any damage.

Cheers

Colyn
Colyn Firth

This thread was discussed between 15/04/2011 and 18/04/2011

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