I believe all the blower motors in Series Alpines and Tigers were
similar, i.e single speed motors with two wires to be hooked up, one to
ground, the other to the ON/OFF switch. In the earlier cars, the ON/OFF
switch was fitted as a push/pull arrangement on the end of the air flow
control lever (I've never seen one which wasn't broken). Later cars had
a toggle switch mounted in the far left hand dash hole under the ammeter
hole. Some cars had a little tag mounted under the toggle switch which
said BLOWER.
These motors are very amenable to being converted to two speeds, and my
S III had a two speed blower which I found very useful. You need to get
a three position toggle switch (Lucas 34281D...same switch as is used to
operate the two speed wipers) instead of the normal two position
switch. One additional item is required to make this work....a 1.2 Ohm
(that's one point two), 30 Watt wire wound resistor, which is typically
about 2 to 3 inches long and 1/2" in diameter. The principal involved is
that the 12 volts (from the fuse panel or ignition switch) is connected
to the input position on the switch, and in its off position this is not
connected to any of the other positions. In the intermediate position,
this power is directed to one of the terminals which is connected to the
blower input wire through the wire wound resistor. This results in the
blower running at about half to 2/3 speed. In the full position, the
power is directed to a third terminal which is directly connected to the
blower, as in the original installation.
Note that when the resistor is working, i.e. the switch is in the
intermediate position, it (the resistor) gets quite warm (that's why it
needs to be a wire wound resistor) due to the amount of power it is
dissipating. As such, when installed under the dash between the switch
and the blower, it needs to be positioned where other wires are not in
contact with it. Wire wound resistors generally come with mounting lugs
at each end which are not connected to the electrical part of the
resistor, so I found mounting the resistor in a clear location was not a
great problem.
On the Lucas three position switch, the terminals are marked with
numbers on the back. The power-in wire should be connected to terminal
1. To minimize the amount of wire required, I suggest you hook up the
output from the switch as follows. Connect a wire from terminal 8 to one
side of the resistor...make sure you connect to the resistor terminals
and not the mounting lugs. From that same terminal on the resistor,
connect a second wire to the power input wire on the blower. Connect a
wire from terminal 4 on the switch to the other terminal on the
resistor. Your wiring is now complete, and the blower should operate at
two speeds.
A few points.
Lucas switches, particularly 30+ year old ones, have a habit of running
out of smoke. If your installation fails to work as I have suggested,
and you are sure you have connected it up properly, you might just try
another switch. The advantage of using Lucas switches is that they are
the same switches as on the rest of the dash.
18 gauge wire should be adequate for this installation, but I generally
use 16 gauge (or larger) for all my automotive work, just to be on the
safe side. I also installed an in-line 20A fuse in the wire feeding the
input terminal of the switch.
If your wipers don't operate at two speeds, it's probably a switch
problem, although after so many years the grease in the wiper drive
system is probably stiff as molasses, and perhaps the motor can't drive
this mess at the slow speed.
Hope this is helpful.
John Slade
Manotick, ON
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