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<DIV><FONT size=2>Firstly I don't really see why a temp sender or gauge problem
should make it run rough under load, but if it's OK now then it's water under
the bridge.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>"</FONT><FONT size=3>But there’s a single heavy brown positive
lead that has a large double black connector (made for two heavy wire leads) but
only has one female connector in it?"</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=2>This sounds like a PO mod to me, there is nothing like that
round any MGB alternator that I'm aware of. Does it carry 12v all the
time?</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>From what I have been able to determine from 69 to 71 a 16ACR
alternator was used that had three connections close together on the back.
It seems that the middle one of these was a large spade and is the output
terminal. To one side of that is a standard spade which is the warning
light terminal, and the third terminal looks like a standard spade but has
chamfered corners as in <A
href="http://www.paulhunt73.webspace.virginmedia.com/mgb-stuff/images/altpm2.jpg">http://www.paulhunt73.webspace.virginmedia.com/mgb-stuff/images/altpm2.jpg</A>.
This was the battery sensing terminal which had a standard gauge brown wire
going back to the solenoid battery cable terminal, as well as the heavy gauge
output wire. This means that under heavy loads the alternator maintains a
better system and battery voltage as it is able to ignore losses in the output
wire between alternator and solenoid.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>That was replaced by a different system, also three pin, but
with two large spades and one standard as here <A
href="http://www.paulhunt73.webspace.virginmedia.com/mgb-stuff/images/altmetro.jpg">http://www.paulhunt73.webspace.virginmedia.com/mgb-stuff/images/altmetro.jpg</A>.
The two large spades are connected together i.e. are both outputs, although at
first only one was used i.e. only two wires to the alt. On later models a
second heavy gauge brown was used to reduce losses under heavy current
conditions and maintain higher battery and system voltage.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Most MGBs probably have different alts now to what they came
out of the factory with, and with the four wiring systems (the first alts had
two plugs and up to five wires) it is anyone's guess how they have been
modified.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>If the warning light comes on with the ignition, and goes off
when the engine is started and revved over 1000 rpm, and if you then see about
14v on the brown at the fusebox, it is charging OK.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>If your mystery brown does have battery voltage all the time,
and you have an unused large output terminal on the alt, then you could connect
it to that. But unless you have added some large loads to the electrics it
shouldn't be needed. In which case carefully insulate the end and tie it
in to the harness somewhere so it can't short to anything.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>PaulH.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=3>----- Original Message ----- </FONT></DIV>
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<DIV>. I got the three prong plug back on, the temp sensor lead and the oil
press transmitter lead all put back on ok. But there’s a single heavy
brown positive lead that has a large double black connector (made for two
heavy wire leads) but only has one female connector in
it?</DIV></DIV></DIV></BLOCKQUOTE></BODY></HTML>