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Re: Electrical puzzle - 1980 MGB

To: "Steve Shoyer" <>, <>
Subject: Re: Electrical puzzle - 1980 MGB
From: "Telewest \(PH\)" <>
Date: Tue, 17 Sep 2002 09:16:42 +0100
Your switch tests correctly, the problem is more likely to be in what the
white is connected to than in the switch itself as there is no wiring to any
of the items that are lighting up near (electrically) the switch itself.

Either a PO wired the side-lights to come on with the ignition or you may
have the fusebox wired incorrectly.  Two of the fuses are connected
internally on one side, this should go to the top front.  Then the wires go
on as follows:

Front bottom (ooer missus) - Brown
Rear bottom - Purple
Front 2nd up - White/brown or white
Rear 2nd up - Green
Front 3rd up - Red/green
Rear 3rd up - Two reds
Front top - Nothing (or the Red/green from front 3rd up)
Rear top - Two reds

The top fuse feeds the side-lights on the LH side the the 3rd fuse up the RH

That could explain the sidelights, but the reverse lights coming on is
probably some other fault to do with the reverse light switch or the wiring
to it.

----- Original Message -----
From: "Steve Shoyer" <>
To: <>
Sent: Tuesday, September 17, 2002 5:17 AM
Subject: Electrical puzzle - 1980 MGB

> I thought I had the lights working OK on my car, but when I was working on
it Saturday I noticed that the side, tail, license plate, and reverse lights
come on with the ignition switch in the "On" position.  I didn't notice that
the last time, but it could have been the case.  I swapped my ignition
switch harness with one from a parts car, but the same thing happens.  I've
disconnected the main light switch that should control most of these
functions, but it doesn't change the result.  I tried testing the switch,
and I think it is working correctly:
> Switch       W   WG  WR  S
> position
>  Off         0   0   0   1
>   I          0   1   0   1
>   II         1   1   0   0
>  III         1   0   1   0
> I believe that the S line goes to the anti-run-on valve, the WG to the
radio, WR to the starter, and W to the normal "ignition on" circuits.
> The strange thing is that I checked the connector where the switch plugs
into the main harness for continuity between pins, and the N, W, and WR pins
showed a connection.
> Does any of this make sense?  I've traced the circuits in my Bentley
manual but I can't see where the problem might be.  I'm guessing there's a
short somewhere - any suggestions on tracking it down?

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