Question---Hi Howard,
I bought a simple continuity tester and here are the results:
The center wire is always hot no matter if I have the directional on to the right, left or off
position. The left wire is hot only when the directional is on to the left. When the switch is off,
there is no power at this wire which is logical. This is the side that works. The right wire is hot
when the directional switch is on to the right (however this is the side the flasher light does not
work). It also appears that tis right wire is hot when the switch is in the off position. Does this
make any sense? I await your reply.
Bob
PS I sent you two photos to longez28 @bellsouth.net if you want to check out the
Jag.--------------------
Followup To
Question -
-- When I opened up the directional switch ( it is on the steering column like a more modern
car), there were three wires on the top and two underneath the switch. I am going to buy an
electrical tester this morning, as I only have a simple tester that I use for my home electrical
work. I assume any twelve volt tester should work. When I test the switch, I assume I place one
on the center wire as a reference and than check the wire on either side of the center with the
switch in the left and right position. Is the polarity important? That is, should I keep the postive
tester at the center or vice versa? Does it matter?-
On a separate note, I understand I need to fill the dash pot on the SU carbs with oil. The manual
says "keep them topped with oil". Does mean to literally fill them until oil is at the visibily at the
top of the opening ready to spill out or visibile down the shaft?
Thanks,
RK----------------------
Followup To
Question -
Hi Howard,
Thanks for your past help. Everything is working fine, except for my right hand directional signal.
The left hand signal works. I changed the bulbs on the right (front and back) and it is still not
working. I assume the flasher unit is OK since the left works. Any suggestions?
Bob
Answer -
Hi Bob,
You are right that if the left works, it is not a flasher problem. That means it is in the switch or
wiring. With a test light or volt meter check at the sw. first with key on and sw. in the right
position. If you have power out to the right side check for power at each joint. You will probably
need a wiring diagram to locate the joints. As I remember the turn signal sw. only has three
wires. Power in from the flasher, left lights and right lights.
I am just working from memory but I think they worked on a resistance of the bulbs. Meaning
that if the rsistance was wrong like one bulb out or disconnected the flasher didn't work correctly
and would give you a steady light on the good bulb. You can check that by checking the left wire
in the left turn position to see what it does to your test light. It may change the flasher speed but
should still work. If your wiring diagram shows a flasher relay with more than three wires than
you will need to follow that diagram to see the current routing. The early 150s had the turn sw.
in the dash and the later had a column mounted sw with a lever like new cars have. Either sw.
should be three wire and tested in the same way.
I hope this helps,
Howard
Answer -
Hi Bob,
Depending on what kind of tester you get as to how you connect it. If you get a volt/ohm meter
you would set it on Low Ohms (with ign OFF)connect one lead to the center terminal and other to
an outer terminal and operate the turn sw. Then check the other outer terminal the same way.
There are several methods to test with a volt/ohm meter. You can set the meter to DC volts in a
range that will show you 12 volts then ground the black lead and use the red lead to check for
powered terminals (this is done with the ign. sw ON. When you use a volt/ohm meter in the DC
volts position it does matter about polarity. If there is a question just check it in both directions.
Read the directions of your meter but all meters I have looked at in the last 30 years are polarity
protected.
For circuit testing like you are doing I like a simple 12 v test light. next best for fast curcuit
testing is a cheap analog (with needle)volt/ohm meter and for accurate testing for ground faults
and voltage drops the expensive digital volt/ohm meter is best.
If you get a test light, leave the turn sw. connected and turn the ign. sw ON. Connect the clipted
lead of the test light to a good ground and with the point of the test light touch each terminal to
see which is "Hot" (power) then turn the turn sw to one side and test all terminals to see which
gets hot. Turn the turn sw to the opposit position and test each terminal again. You will then get
a picture of what gets power and when.
The oil in the top of the SU carbs is a dampener to stop the piston from moving to quickly. It also
evens out the pulsations of vacuum at idle. Generally the thicker the oil viscosity the richer the
mixture on a quick throttle opening. I use what ever engine oil I am using at the time. Meaning I
use 10w30 in the winter and 20w40 in the summer on MGs, Triumphs and Jags. If the engine has
a lot of miles on it I step up one grade from that. Some mechanics I know don't like it that rich so
they use 10w all the time. (I don't like the risk of the spit back into the carbs on a cold day or
cold morning which can cause a lot of damage) so I laugh at them when they get it.
Howard
AnswerBob,
Disconnect the wire at the first junction of the right wire and test the wire and the right terminal to see if the power is coming from the wire or the sw. It is not normal to have power on that wire. You will need a wiring diagram of your car to proceed. I don't have one but will see if I can acquire one. Does the turn signal sw have a short wire harnes attached with individual plug-in terminals on the end? If so look closely to see if the color codes match that are plugged into them. Respond in an e-mail direct. longez8@bellsouth.net
Did receive your photos but have not had a chance yet to put them on my website. Plan to upgrade my site in a few days.
Howard
