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MG MGB Technical - Park/Turn Signal Differences

I have a 1971 mgb roadster (I think). The front parking/turn signal assemblies are both bad, and I purchaesd two on eBAY. The only problem is the new ones are for 62-69, and only have a green and a black wire. My car has a green, red and black wire. Both the old and new ones have only one lamp in them. Is there any way I can connect the new lights to the existing wiring, and still have parking lights and turn signal lights? Thanks.
Curt

Hey
The early lamps you bought should have two bulbs, the outer ones when looking at the front of the car, are the paring lamps and the inner ones are the signal lamps. The green wires are for the signal lamps and the reds are for parking lamps. If your newly purchased lamps have two wires only, each one going into the back of a bulb housing, the ground, which would be black on your original ones, is a contact connection with your fender. Hope this helps, I have put the two bulb setup on all of my CB MGB's, if you need pictures, I can provide them.
Jake

Curt,
In Lucas land, Black wires are ALWAYS ground (there are a few rare exceptions, most or all on motorcycles). If they are some aftermarket or strange supplier they could be different. Early lights frequently had a push-in connector for ground, clearly electrically and physically attached to the lamp body.
As Jake says, early lights should have two bulbs, and it is obvious where the wires go. If there is a single socket, remove the bulbs and see if it has one or two contacts. If it has two, look in the bulb and see if it has two filaments. If there is one bulb, with one filament, then it is a one beam light and is NOT for this application. There are similar lights that have only one circuit. If it has two contacts AND two filaments, it will work. One wire should connect to each contact, and ground is through the lamp body.
Is there a part number and manufacturer shown on the lamp or box?
FRM
http://www.usachoice.net/gofanu
FR Millmore

Guys, Thanks for the information, but I need to clarify things. The new signals are Lucas L677 assemblies. I don't know what that corresponds to in Moss. The bulbs that are in the new base are one filament. However I do have Moss 170-700 DOUBLE filament bulbs that are designated in the catalog for the correct 1971 signal assembly. Also, there are two wires, one green (hot) and one black (ground). I have three wires in the wiring harness, red, green and black. There is only one bulb in both the new and old assemblies. Can I hook the red and green in the harness to the green in the new signal assembly, and use a double emlement bulb? Clear as mud, huh? Thanks. Curt
Curt

If you can, pull the bulb out of the base and look down where it sits. If the base is correct for a '71, it will have two brass contacts at the bottom in a piece of bakelite that is springloaded. The bulb should also be dual filament. If you don't find this is the case, you have something that won't work in your car.
Jake

Curt,
L677 is a model of basic lamp, not a part #, and has many variants which are different. The part # is a 5, 6, or 8 digit # usually. There are cars that use a similar light to the B as either a park or TS lamp, but I can't remember what offhand.
No, you absolutely cannot put the two filament bulb in that light. Do the two wires connect to the plastic insulator inside the socket via two metal contacts? If so, you can find special bulbs at a good parts store which have two filaments and two contacts, but with non-offset pins. On single filament bulbs, the two pins that stick out the side to hold it in are not offset, because it doesn't matter which way round it is. Standard two filament bulbs have offset pins so that you can only put them in right way round. It's possible to change the internals of a one contact socket to two contact ones, again you need the special bulbs. The special bulbs were made long ago, when people were putting turn signals on cars that did not come with such. If you can't find them, you can get by with filing off the pin that doesn't line up on the standard two contact bulb, but it is a bit shaky. Then you would plug the green wire to green, the black wire to red, and run a ground, which should be black, to the harness ground -black. Put the bulbs in so that the dimmer filament is on as a parking light.
I have somewhere listings of these bulbs, but get specific on the description first.
Any more questions, email me direct, it's getting a bit arcane!
FRM
http://www.usachoice.net/gofanu
FR Millmore

Just an add on:

There should be thre wires -- a green, red and black -- the unit should have two bulb sockets -- one parking the other turn signal.

When buying from e-bay, caveat emptor.
glg

Well, guys, the socket does not have two contacts, and there is no second live wire to go with the green and black. I do have the wrong lamp assemblies for my 71. What is really confusing is that the Moss catalog shows two bulbs in the base of the assembly for 62-69 MGBs. The base on this one has the space and punchout for the parking lamp, but it is not cut out. I wonder if the assembly I have is for an MGB at all? Thanks for your help. As FRM says, caveat emptor. Curt
Curt

Curt, and everybody else, please read carefully. As Jake said, there is NOTHING confusing about Moss showing two bulbs: they HAD two bulbs then, later they had one double filament. I told you that L677 is a basic lamp MODEL, and comes in a number of specific variants, each with its own part number, each for a different application. I also told you that L677 comes as a single bulb, single filament light for some other car -that is evidently what you have. Also told you how to tell what's what, and how to fix it.. And, to email if you have more questions, but there is no email here. And, I didn't say Caveat...., but I will if you like. Now that I'm done yelling, email me, or go to a REAL parts store (heavy truck suppliers can be good) if you can find one, and talk to a greybeard with lamp in hand.
FRM
http://www,usachoice.net/gofanu
FR Millmore

This thread was discussed between 30/05/2004 and 31/05/2004

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