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MG MGB Technical - front & rear light problem

Problem with 70 B" lights. Both my right rear "red" tail light and front right parking light won't work. The problen isn't bulbs. They must share a common wire that has shorted out. The front parking/turn signal light was burned out. Anyone have thoughts of were the problem might be?
Frank Hill

Hi Frank.

I guess that one of your number plate lamps is also out ?.

I would start by looking at the fuse that feeds the right-hand side lights.

HTH... Don
Don

Frank, Don, has the right sugesstion. If you will look at your diagram of the fuse block you will see that a red/green wire from the lighting switch feeds a common terminal for both left and right parking lights through two separate fuses at the fuse block. One fuse is for left side parking lights the other for the right side. If the left lights are working then there is a problem with the right side fuse, fuse holder (very common, needs cleaning) or the wires leading to the lamps. It would be unusual to find both wiring circuits defective in another type vehicle but with a MGB?...........I've seen weirder problems.

Dann BCC
Dann Wade

May also be your light switch. I had a '70 that had the internal plastic rocker melt, but only just enough to prevent contact on the running lights position, the headlights worked fine.
Jake

Don, check your fuses. Could be just a bad connection. One fuse goes to the right front/left rear and the other to the left front/right rear. A bad light switch would take em all out.

cheers
Doug Gordon

The fuses *should* feed separate sides, not separate corners, the top fuse feeding the right side and the next fuse down the left. Depending on how they were last connected up the sides could be the other way round.
Paul Hunt

I have a '72 that exhibits the same problem intermittently. In my case it's a poor connection in the wiring bundle near the horn. a little wiggle and presto....problem resolved (tempoarily) I really should do a permanent fix one of these days!!!!
JR Ross

Dann
The colour of the wires that feed the side lights, rear lights and number plate lights is plain red, red and green is LH indicators.
Frank
Have you checked to see if the lights are earthing properly? [ black wire ].this is quite a common fault with wiring systems,the rear lights are held on by earthing nuts which must be kept tight
H.E.W. Walker

H.E.W.

The wire that feeds the fuses for the parking lights is red/green, as Dann stated. The LH turn signal wire you speak of is green/red. There is a difference, altough sometimes it's hard to tell.

After the fuses, the wires are red.
Dan Masters

a chrome bumper MGB did not have earthing wires on either the rear light clusters or the front parking/turn light clusters, they all earth via the physical fixings.
Paul Hunt


Dan
Yes, I was thinking of the cars up to 1967 where the side/tail lights don't go through the fuse box. Agreed I should have said green with a red tracer for the LH indicators
H.E.W. Walker

This thread was discussed between 07/03/2004 and 11/03/2004

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