The '76 Midget had two, possibly three diodes depending on if it is a
California or a federal spec car. All had a diode for the EGR service
interval counter and the Brake warning light. California cars also had one
for the Catalytic converter service interval counter. The diodes energize
the warning lights by receiving power from the white wired ignition circuit
when you turn on the key to indicate that they are working. If a diode or
diodes goes bad you end up passing power through the diode from the green
(power-key on) circuit to the white (power on ignition) circuit. This
routing of power through the diode in the wrong direction keeps the starter
energized when you turn the key to the on position. If the starter did not
turn off when you turned the key to the off position it sounds like you may
have the wires routed wrong through the ignition switch.
I highly recommend that you buy a copy of the MG workshop manual for the
1975-1979 cars and a test light. You will not regret having them when you
are working on these systems. I had a diode go bad on my '76 and on Ed's
(lbcnewby) '78. We would have never figured it out by trial and error.
Wire colors for reference:
Black Ground, unfused
Brown Always hot, unfused
White Hot with ignition on, unfused
Purple Always hot, fused
Green Hot with ignition on, fused
Red Parking lights, fused or unfused
Blue Headlights, unfused
Light Green Various applications
Slate Hot with ignition off, fused and unfused
Yellow Hot in 3rd/4th, ignition on Fused
Good Luck
Rich Ball
'76 Midget
Everett, WA
-----Original Message-----
From: spridgets-bounces@autox.team.net
[mailto:spridgets-bounces@autox.team.net] On Behalf Of Gerard
Sent: Monday, November 28, 2011 1:44 PM
To: spridgets@autox.team.net
Cc: midgetsprite@yahoogroups.com
Subject: Re: [Spridgets] Line diodes
The schematics I have for the 1500 indicate the diode is present in
Midget MKIII USA (car no G-AN5-101501 onwards to the end of 1977
production) and Midget MKIII UK (1500 models to the end of 1977
production)
A time delay relay and 2 diodes are shown in 1978 onward schematics.
Gerard
On Nov 28, 2011, at 11:00 AM, spridgets-request@autox.team.net wrote:
> Message: 8
> Date: Mon, 28 Nov 2011 06:05:13 -0800 (PST)
> From: Skip Jackson <jackson.skip@yahoo.com>
> To: spridget <spridgets@autox.team.net>
> Cc: midgetsprite@yahoogroups.com
> Subject: [Spridgets] Line diodes
> Message-ID:
> <1322489113.48736.YahooMailClassic@web46408.mail.sp1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> When dealing with complicated wiring I refer to 'Classics Brit Car
> Electrical Systems' by Rick Astley. Thankfully I have not found any
> diodes in AN5L/37190; yet. Skip J
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