Tue, 28 Oct 1997 08:58:34 +0100 John Van syckel
<vansyck@hq.1perscom.heidelberg.army.mil> wrote
Subject: Slooow Directionals
< Quick question which probably everybody know the answer to (except me).
< The directionals on my 1971 MGB blink at normal frequency when the
< headlights are off. When the headlights are on the right one flashes
< much slower and the left one even slower than the right one.
< What do I look for?
Jay:
Usually, when the turn signals get slow, there is either a bad connection or
undersized bulbs at fault. If both sides are slow, the bad connection is in
the supply side. If just one side is slow, the problem is usually a bad
ground connection on that side. Turn signal flashers are particularly
sensitive to reduced voltage or current. They are made this way on purpose to
provide a warning when there is a problem - otherwise, you could go for years
without knowing that the lights are not working (not you, of course, nor any
other LBCer; I'm speaking of the great unwashed civilian population here!)
Since your turn signals work fine till the headlights come on, your turn
signal circuits are OK (well, there is a small problem in the left side,
since they are a little slower than the right). The problem lies somewhere in
the circuitry where the two circuits are common. Because these two circuits
(headlights and turn signals) are separate, there is no current sharing, so
the problem has to be one of reduced voltage. Somewhere, in a connection that
feeds power to both circuits, there is a bad connection. With the lower
current drain of the turn signals, the resistance of this bad connection is
not enough to drop sufficient voltage to be a problem. With the added current
draw of the headlights through this connection, though, there is enough
current to produce a large voltage drop.
What you will need to do, is check the wiring that is common to both
circuits. You will only need to look at the power side, not the ground side,
because we know the grounds are OK, or the turn signals wouldn't work with
the headlights off.
Power to the headlights comes from the battery to the headlight switch via a
Brown wire. Power to the turn signal flasher comes from the battery to the
ignition switch via a Brown wire, from the ignition switch to the fuse box
via a white wire, from the fuse box to the flasher via a green wire. The only
wires in common are the Brown wires. There is where you should be looking.
Check all of the brown wires and all the connections in these wires. When
these have all been checked and corrected, the turn signals should work fine.
While you are at it, it would be a good idea to check ALL the wires and
connections in the car, and save yourself problems later on down the road.
Good luck!
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/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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