In a message dated 97-10-12 14:53:52 EDT, naffy@netins.net writes:
> If Mr. Masters could explain the wiring from relay all the way back to od
it
> would be very helpful.
Be glad to, Gary.
First of all, let's identify the relay, if you have one. From the factory, a
relay was used for the O/D from the TR250 up to TR6 model year '74. Beginning
with '74, the former O/D relay was confiscated to serve as a starter relay,
and the O/D was wired direct. The following applies to the TR250 as well as
the TR6.
As Triumph didn't always do what they said they did, or conversley, didn't
always say correctly what they did, there can be descrepancies in the wiring
configuration af any given Triumph. That said, look at the relays found on
the inside of the drivers front fender, near the clutch M/C, and determine
the color code of the wires going to them.
If the relay has one or two purple wires, one purple/black and one
purple/yellow, it is the horn relay. If it has two purple/red, two green/red,
two green/white, one light green/pink or green/brown, and one black wire, it
is the hazard flasher relay. If it has one or two brown wires, one white/red,
one white/orange, one white yellow, and one black, it is the starter relay.
If it is the O/D relay, it will have one white wire, one brown, one
yellow/purple, and one yellow/green.
Next, look at the transmission. There will be two or three switches mounted
to it, depending on the model year. One of these will be the reverse switch,
which will have one green wire and one green/brown wire. The other switch(es)
will be the O/D inhibit switch(es).
Since your car is a '69, with a '73 engine, you should have a relay, so we
will start with that. The relay will have four or five terminals on it,
labeled W1, W2, C1, C2, and if there is a fifth, it will be labeled C3 or C4.
W1 and W2 are the terminals leading to the relay coil (W)indings (hence the
"W"designation), and C1, C2, C3, and C4 are the terminals leading to the
switch (C)ontacts (hence the "C" designation).
The power feed to the relay comes from the brown wire, (the brown wire is hot
at all times and is not fused), which should be connected to the C1 terminal.
Power to the solenoid from the relay comes from the C2 terminal, when the
relay is energised, via a yellow/purple wire. Power to operate the relay coil
comes from the white wire (the white wire is hot only when the key is on and
is not fused).
All that is left now to get power to the solenoid is a ground connection for
the relay coil. We have power to the relay contacts, power to the relay coil,
and and a path from the relay contacts to the solenoid. When the other side
of the relay coil, the W2 terminal, is grounded, the relay is energised, the
internal relay switch contacts C1 and C2 will close (C1 and C2 are shorted
together inside the relay), and the solenoid will be energised.
Two things are required to get the relay coil grounded - the O/D switch must
be on, and the transmissiom must be in the proper gear. From the W2 terminal
of the relay, a yellow/green wire goes to the O/D switch. From the O/D
switch, a black wire goes to a connector. On the other side of this connector
is a yellow wire. The yellow wire then goes to one of the inhibit switches,
>From there, it jumpers over to the other inhibit switch (it doesn't matter
which one is which, for our purposes). The O/D switch is not polarity
sensitive, so it doesn't matter which way it is wired - ie, the power could
go to the black wire, and then through the yellow/green wire to the inhibit
switch(es). The same is true of the inhibit switches - it doesn't matter
which terminal is which.
There is a black wire from the other side of the inhibit switch, which goes
to groud and to the other side of the other inhibit switch. Since the inhibit
switches are wired in parrallel, if either one of them are closed, there will
be a ground path up to the O/D switch. If the O/D switch is in the ON
position, the ground path will continue to the relay terminal W2, and the
relay is energised, operating the solenoid. If the transmission is not in one
of the "correct" gears, neither of the inhibit switches will be closed, and
the ground path is broken. In the correct gear, at least one will be closed.
What if you don't have a relay, or prefer not to use one? This set-up is even
simpler. If the car came without a relay, power to the solenoid takes the
following path: power is supplied by a green wire (green wires are hot only
when the key is on, and they are fused), which connects to the yellow/green
wire from the O/D switch, through the O/D switch, via a black wire, to the
connector and a yellow/green wire, to the switch(es), wired as before, and
then to the solenoid. It is important to note that the inhibit switches go to
the solenoid and NOT to ground, as they did when the relay was used. If they
are grounded, there will be a dead short from the green wire fuse to ground -
not good!
If you wish to eliminate an existing relay, just rewire the car as above,
using whatever color of wire you have available. The inhibit switches and the
O/D switches are the same in either case. To test the solenoid just jumper
directly from the battery with a large wire. Watch carefully for a shorted
condition so you can remove the wire quickly if there is one. If the solenoid
is OK, you should hear, or feel, it operating - there are no other interlocks
involved.
Hope this was of some help to you. If I left anything out, or you need
anything else, please let me know.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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