In your note (which I will pass on to Dan, and is included below) you mention
that your car is 74217. This pretty definitively shows that the late cars had
the flash to pass function energize the highbeam wire only. Mine is 73336 and
I had one other person give me their commission number, also in the later half
of 4A production. Please do take a look at the harness and see if you can
tell physically where the wire enters the high beam part of the harness. I
guess that pretty clearly it does it and does it under the dash
somewhere.....
Does anyone having an "early" 4A, say in the 50000 to 60000 range with pretty
original wiring have this same flash to pass function? I'd like to establish
a change-point if one exists. This may be one of those things where the
engineer who drew the diagram did not speak to the guy who laid out the
templates for the harnesses.
-Tony
______________ORIGINAL MESSAGE___________
Date: Fri, 3 Dec 2004 15:21:44 -0800
From: "January Williams" <january@chemeketa.edu>
Subject: RE: more on TR4 and 4A flash to pass
My stock TR4A CTC 74217 LO (built Nov 66) has the 'advanced'
flash-to-pass, where it flashes the high (main) beams whether the
headlights are off or are on low (dipped). Although no one else has so
noted, the high / main beam indicator light on the Speedo dial is also
flashed. My harness wiring (which I have no reason to suspect is not
original) differs from that given in the "Triumph TR4A Owner's Manual"
fig 56 on page 42.
In fact, my wiring strongly resembles the wiring associated with the
light switch on Dan Master's 1969 TR6 draft diagram which is page two of
his pdf of the 6-cyl cars (orig filename is TR250-6.pdf, note the
70-71TR6 wiring appears similar, but by 72 the dipper switch is
different, and by 73 it looks like the headlight switch is on the panel
like the sidescreen cars).
I've been meaning to do a trace and post the results here and to Dan,
but I haven't gotten to it.
For example, the flash tap on the light switch (UW) connects to a double
bullet with a pair of UWs in the harness, contrary to the owner's manual
diagram which shows the flash tap mated to the main beam line, also from
the light switch (U) and the harness line to the dimmer, UW.
Another comment about the functionality and why it may have arisen. I
don't know about British driving habits, whether flashing the lights has
been common for a long time or not. My first sports car was an 63 ALFA
Gulia 1600 spider, and the owner's manual for it explained the flasher
(which was a concentric ring in the steering wheel) that sounding the
horn was outlawed in certain Italian cities, and the flasher was used at
intersections at night. As I recall it was more sophisticated and would
flash the lights off if the high beams were on in addition to the
behavior in my TR4A. Although Jonmac made no reference to this, I think
it might be possible that the flasher capability was upgraded a bit to
make the cars more attractive in the continental markets, just a WAG,
really. As soon as I am feeling up to it I will crawl under the scuttle
and verify the harness for the light switch.
cheers
january
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