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MG MGB Technical - Ignition switch wiring

I have a 72/73 BGT (UK) with what appears to be a different locking steering column ignition switch..i.e.it has 6 blade terminals. My problem is that I am trying to connect up my new wiring to this switch, but cannot figure out what to put on where! The new wiring loom has 5 leads, which is standard for this car. The switch is an SWF type (Germany). The blades on the back are marked 30 (2 blades), 57a, 15, 50, and 75...what these all mean I don't know. The switch number appears to be 800068.
I have spoken to Paul Hunt, and looked at his schematics, but still can't work it out.
Can anyone enlighten me on the connections?
BTW, the key side shows O,I,II.
Gary Lock

Gary,

30 is + from battery (brown) , 57a is for parking lights, 15 runs to the ignition (white), 50 goes to the solenoyd of the startermotor, 75 ??? never had this before, recheck or mesure.

Hope this helps

Ralph
Ralph

Gary,

Mine sounds exactly the same as yours - gibberish markings that don't match any wiring diagram. It took hours with a circuit tester and the ignition key in different positions to work it out.

I will crawl out into the snow later today and have a look. I'll report back.

Liam
Liam

Brrr, it's cold out there.

Right, what I can see on mine is this.

Looking at the switch from the rear, Starting at the opposite end to where the key goes in (ie the other end of the barrel).

There is a double spade here - takes two lots of double white wires.

(Then going anti-clockwise)

Double spade - single red/white wire.

Then green/white wire - can't tell if its a double spade or not.

Then an empty single spade.

Then a double spade with a single brown wire.

Then the double white wire spades again.

HTH
Liam
Liam

Thanks everyone so far..Paul, looks like there is another type of ignition switch in some of the 72/73 cars..mine appears to be original.
Ralph, rechecked switch, and there is also a number 16 where I said 75.
Gary Lock

Gary,

No. 16 is a bridged supply for coils using a resitor!

Ralph
Ralph

Wikipedia DIN27552 gives 75 as radio, cigarette lighter i.e. accessories. That list doesn't have a 16. It agrees with 57a as being parking lights but wiring for this doesn't come off the ignition switch in an MGB, neither does the contact to bypass the ballast resistor (rubber bumper cars only) if this is what Ralph is referring to in his comment on terminal 16.

The implication is:

Brown to 30 12v in.
Green/white 75 accessories out i.e. first position of switch.
White to 15 ignition out i.e. 2nd position of switch.
White/red to 50 starter i.e. 3rd position of switch.

But confirm these with a meter or test-lamp before making any connections.
Paul Hunt 2

Paul,

here are the codes for electrical systems on cars, using the BOSCH scheme up to 1977


Ignition and Starer
1 low tension (coil to distributer)
4 high tension (coil to sparks)
15 exit ignition switch (switch to coil)
15a entry for high voltage ignition blackbox or coil resitor
16 jumper for bridging the coil's resitor during starting

Battery
30 direct entry from batt (+) terminal
31 direct lead to batt (-)
31b negative earth ground
50 starter control from ignition switch

Generator/Alernator/Regulator
61 alt./gen. teminal for ignition light
B+ alternator (+) or regulator (+) when generator fitted
B- as B+, negative line
D+ Dynamo (+)
D- as D+, negative line
DF dynamo field

Lights
54 breaking lights and other consumers
55 fog lights
56 driving lights, connetion at the switch
56a high beam and high beam control light
56b driving light
56c fractional high beam
56d headlamp flasher contact point
57L left hand parking light
57R right hand parking light
58 positon lights, rear lights, license plate lights, instrument lights
58L rear lights and position lights LH
58R as 58L, RH

Direction Indicating Lights
49 flasher unit (+) entry
49a triggerd flasher unit exit (to direction switch)
C flasher indicator light at the dash (single blub version)
CO main terminal if two directin indicating contol blubs fitted
C2 second terminal for trailer flasher control light
L direction indicating flashers LH
R as L, RH

Whiper and Washer
31b wire back from whiper motor via short-switch to ground
53 whiper switch (+)
53a whiper (+) endstop
53b whiper (?? Nebenschlusswicklung?? sorry,but i have learned English from my MG manuals and by listening to the radio)
53c washer pump
53e whiper breaking coil
53i 3rd. brush (for 2nd. whiper speed)

Relais
85 relais coil (-) or ground
86 relais entry (+)
87 relais entry (opening or changing points type)
87a as 87, open end
88 relais entry (closing points type)
88a relais exid (opening and changing points type)

Hope this helps

cheers

Ralph














































Ralph

This thread was discussed between 23/01/2007 and 24/01/2007

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