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MG MGB Technical - Turn Indicator

1978 MGB
Looking for picture of dis-assembled turn indicator/plastic housing. The horn works when it wants to, not when I want it to. Replaced horns with original high/low and replaced what wiring I could.

Bought "new" turn indicator on EBAY. Horn works, but nothing else works. When testing the new indicator, it was not installed on the column--I plugged it in the harness and was holding it in my hand. Does this need to be grounded even when testing?

Wiring diagrams won't show me the guts of the housing or how the springs and brass bits inter-relate. I figure with pictures/drawings, I can at least muddle one working switch out of two.

thanks
Shook
shook

Before you start muddling connect a ground wire to the indicator to see if everything works.
Mike MaGee

Shook, The switch is a routing device and shouldn't need grounding. I checked several column switches a couple of years ago with a multimeter. I used the ohm meter to check switch operation for each individual switch. With switch on there should 0 ohms resistance. Switch off there should be infinity resistance.

I don't know of any individual switch diagrams for the signal lights. Windscreen switch diagrams are on Paul Hunt's web site. I used a wiring diagram to identify the wires by color code to make my resistance checks. You can find a color coded wiring diagram for your car here.
http://mgcleveland.hmcltd.net/mgwiring.htm
Check each pair of leads until all the switch functions have been tested. The combination switches for signal lights on 68-74 chrome bumper cars are riveted together and aren't something you will want to take apart. Most of the contacts are accessible without any dis-assembly.

Clifton
Clifton Gordon

Another source of color coded wiring diagrams is at http://www.advanceautowire.com Just click on the "stock schematics" button.

These diagrams have not only been color coded, but they have been redrawn to make them easier to read as well.
Dan Masters

Thanks for the info and diagrams. The plastic housing (with guts) is screwed to a metal plate which goes over the steering wheel stock. The tension doesn't feel right when I move the indicator to the left turn position. Feels spongy and won't stay in position by itself. Almost feels like a spring is out of place or missing all together.
Shook

As Clifton says the wiper and indicator switches don't use grounds, and even the horn switch on that model (button on the stalk) didn't use one either but connects purple (used 12v) to purple/black. Mechanically the switches are very simple, they just bridge adjacent pairs of contacts around an arc. Are you sure you are moving the indicator far enough? I replaced a 73 model and found it much stiffer, 'spongy' before it clicked over described it well. If it didn't have a return spring (or springs) it would be loose and floppy about the centre position. The latching mechanism *should* be external and visible (it was on the earlier types) as a clip on the rotating column lifts moving fingers off a locking post to allow the switch to return to its central position, so when you operate the switch you can see these moving fingers and how far you have to move them to lock behind the post.
Paul Hunt 2

Paul,

I'm throwing the switch far enough in both directions. It will catch, but sporadically and with some assistance. Upon closer examination, I saw something lodged in between the metal retaining plate and plastic housing, stalk side. Appears to be a brass pin lying on its side, not really contributing to anything. Looks like it's about 1/8 - 3/16ths in length, diameter about 1/16th inch. Coated in elect grease, and doesn't appear to be connected to anything. Should this be providing electrical connectivity within the switch assembly or is it used as a "Stop" for the stalk?

Again-thanks for helping me with this

So many parts-not enough time

Shook
Shook

This thread was discussed between 03/10/2005 and 06/10/2005

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