408 windscreen wiper motor wiring

[David Olivant]

The wiring diagram for my 408 shows the colours of the wires on the Bristol loom. It does not however show which wire connects to which of the braided wires coming from the motor!

Can any-one help?

I have sorted out the rest of the wiring including adding in a relay for the headlights and a main ignition system relay.

This wiper motor issue is stopping me going for an MOT when I return from holiday.

regards,
David

posted by Kevin Howard on behalf of David

[David Olivant]

Via B.M. in London spoke to Sid Lovesy{?} at the factory who promptly gave me the correct wiring.
Wiper motor working as it should. A happy bunny!

[lansdownplace]

Sid designed the wiring for all the cars between the 400 and the
Blenheim, there aren't many car companies where you can get advice
directly from the designer, especially on models stretching over 63
years

Paul

[Kevin H]

Originally Posted by David Olivant

Via B.M. in London spoke to Sid Lovesy{?} at the factory who promptly gave me the correct wiring.
Wiper motor working as it should. A happy bunny!

David, please share the details on here for the benefit of other owners

Kevin

[David Olivant]

On looking back the wiring is remarkable simple.[they always say hindsight
has 20/20 vision].
The wires from the switch in the loom are all designated by a LIGHT GREEN
main colour.
The trace colour matches with the similar coloured wire on the motor loom,
eg red to red, blue to blue etc.
These motor wires look like VIR braided cables and discolour and fade
easily. If you strip back the sheathing containing them the colours are
easier to see, they may still be faint however. resheath on completion.
Of prime importance is the earth [BLACK] wire on the switch. If you do not
know if it is a good earth I would suggest another earth wire is run to a
good earth point.
These older motors have a field coil and protecting that a bi-metallic
switch inside the casing.If you are stripping the motor for a clean, brush
check, and wiring check, clean these contacts with either a needle file or
glass paper.Similarly clean and lightly undercut the commutator. Assemble
and repack the bearings with a smear of grease and fill the gearbox with
new grease. Check the park switch contacts and clean. Watch when replacing
the gearbox cover that the park switch stays in place.
Do not attempt this in place, a divorce will follow!
Hope this assists.
David

[geo]

Originally Posted by David Olivant

On looking back the wiring is remarkable simple.[they always say hindsight
has 20/20 vision].
The wires from the switch in the loom are all designated by a LIGHT GREEN
main colour.
. . .
Check the park switch contacts and clean. Watch when replacing
the gearbox cover that the park switch stays in place.
Do not attempt this in place, a divorce will follow!
David

From my memory of doing this thirty years ago (I wish I had thought of asking Sid Lovesy!) this is really useful advice — especially the bits about the parking switch and not attempting to do this in situ!

It is really worth doing as even way back then, it made a tremendous improvement to the wipers (and why not go the whole hog and replace the gears on the spindles — or, if no-one has done it before you, rotate them through 180º).
George