In a message dated 98-12-01 17:57:24 EST, vitesse@juno.com writes:
> The turn signals don't work and haven't for awhile.
>
> So my questions are. Does the steering column switch supposed to have
> power in it? Or is it supposed to be grounded? Mine is grounded. The LG
> wire going to the switch is grounded. When I test it with a test light,
> I get left and right circuit completed as if it is supposed to be a
> ground.
Hugh,
Yes, the TS switch is supposed to have power to it whenever the key is on (and
the hazard switch is off). I'm curious as to how you determined the LG wire
was grounded. I assume you disconnected it from the flasher side, connected
the alligator clip of the test lamp to the battery, and touched the probe tip
to the wire, while operating the TS from one side to the other? Did the lamp
light when the TS switch was off? I think it didn't.
Normally, that's the way one would test something like this (continuity
checking), but this test can be very misleading when testing light circuits.
I'll explain: The bulb used in the test light is a low wattage bulb compared
to the turn signal bulbs. Being a low wattage bulb, it has a high resistance
and draws only a small amount of current to make it light. The TS bulbs, by
comparison, are low resistance, high current devices. When the test light is
placed in series with the TS bulbs, the TS bulbs look like a good ground to
the test light, because of their relatively low resistance, and the test light
lights up so close to its normal brilliance that the difference is not
noticable. The high resistance of the test light limits the current, so the TS
bulb will not light.
Continuity checks are valuable, but they can be very misleading. It's
mandatory that you have a schematic when using continuity checkers, and that
you study it carefuly when doing this type of test. When I was wringing out
the wiring in my TRV8 project, I found a dead short between two fuses. I
reviewed the schematic, turned off the headlight switch, and every thing was
OK. What was happening, was the current from the continuity checker was
traeling through the first fuse, through the courtesy lamps, through the car
body, through the parking lamps, through the headlight switch, and then to the
other fuse. It looked like a dead short from one fuse to the other.
> The G wire going to the flasher is hot all the time the key is turned on,
> and the LG wire on the other side of the flasher is also hot all the
> time. Isn't that wire supposed to be the same that goes to the column
> switch?
According to my diagram, that is supposed to be a LG/N wire, but yes, it
should go to the TS switch, and there should be power on it any time the key
is on, EXCEPT...... when the hazard switch is on. And there is 99% of the
problems with turn signals not working. In one position, the hazard flasher
has power (and this will also explain why you have no power to the hazard
flasher, I think), and in the other position, the turn signals do. In your
particular situation, the hazard switch is neither in the hazard position nor
the TS position. Physically, it is in the TS position, but because of an
accumulation of crud inside, the TS contacts are not closing properly.
Try this: With a piece of wire, jumper from the LG/N wire at the TS flasher,
to the LG/N wire at the TS switch. I'd almost bet that your turn signals will
work when you do (key on, of course).
If they do, you have two options: remove the hazard switch, take it apart, and
clean it. Or, buy a switch from Radio Shack and bypass the hazard switch. I
took the latter approach, as the hazard switch would only crud up again in
time. The contacts in the hazard switch have a wiping action as they open and
close, which is intended to keep the contacts clean, but the switch is
operated so seldom, that they just stay crudded up. Operating the switch very
often will help allieviate the problem. but won't cure it, unless you operate
the switch VERY often.
I have a JPG of the wiring changes needed to make the change, if you are
interested. It is VERY easy to do. If you want to keep the stock appearance of
the dash, you can leave the hazard switch in place and hide the replacement
under the dash, out of sight. You could just leave the jumper you used above
in place, but if you do, don't ever use the hazard flasher when the turn
signals are on if any thing else in the car is on. That's a long story, but if
you are interested, I have a brief write-up explaining it that I can send you.
> The 4way flasher has no power to it, out of it or anywhere around it.
It won't have power unless the hazard switch is in the hazard position.
To see if the hazard switch is the problem, turn it on, and jumper from one of
the purple wires at the fuse box, to the purple/red wire on the flasher. If it
is the hazard switch that's the problem, your flasher should now work.
> I have replaced both flashers with new from the store...is there anyway
> to field test them?
You can test the hazard flasher by connecting a bulb to the "L" terminal,
while connecting the "B" terminal to the battery (on some auto parts store
flashers, the "B" terminal is marked as "X"). You can test the turn signal
flasher the same way, but it takes two bulbs to get it to work (assuming you
really have a turn signal flasher, rather than a hazard flasher - most of the
turn signal flashers sold in the stores are really hazard flashers). This is
also a long story, but if you are interested, I can send you the details in a
later post.
> Now I am really LUCAS Electrics challenged when things don't the way that
> I think they should, so if anyone should feel so inclined to
> respond....please keep it really simple.
I hope the above was simple enough to understand, but deep enough to help you
solve the problem. If not, let me know, and we'll try again. (BTW, no need to
use a fuse in the jumper leads for the above tests, as the exisiting fuses
will provide protection)
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/index.html
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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