Shucks, I haven't answered one of these for a while. BAD GROUND.
At 05:58 PM 7/13/2000 -0400, Bill Saidel wrote:
>Why does the right turn signal stop blinking for 10 seconds when I step on
the brakes at night (with the headlights on) before it starts flashing
sloooowly but the same behavior is not demonstrated by the left turn signal?
>
>During the day it is not as bad but the flashing rate is not "vibrant".
Turn signal flasher rate is determined by current draw. The flasher unit
is designed to flash normally with the specified load, two 21 watt bulbs
for most MGs. If the load is not correct it will flash faster or slower or
not at all, giving a noticeable indication that something is wrong with the
circuitry or that a bulb is burned out. A burned out bulb reduces the
current draw and causes it to stop flashing. An extra bulb in the circuit
(plug in my trailer lights) increases the current draw and causes it to
flash slower (at least on my MGA), but could cause it to flash faster with
other flasher units, or to have a shorter flash but at the same frequency.
Most common cause of no flash is a disconnected or burned out bulb, pretty
obvious because it doesn't light up. Next common cause of either no flash
or slow flash is a bad connection that introduces more resistance to the
circuit and reduces current flow. For this you need to check and clean all
the electrical connections in the offending circuit, especailly the
grounding points on the body of the car.
>The emergency flasher seems to be unaffected.
The emergency flasher is constructed differently, such the it will flash at
roughly the same rate regardless of electrical load. The idea here is the
it should always flash in an emergency, even if one or more of the bulbs is
not working, such as a burned out bulb, smashed lamp fixture, etc.
>Is it current or voltage that is being lost to the turn signal flasher?
Where does it go and what part(s) need to be replaced?
Unless the battery voltage is low, you will always have full battery
voltage applied to the circuit. Each device in the circuit has a
particular resistance, and will therefore draw a certain amount of current.
As circuit resistance increases (bad electrical connections) the current
draw decreases. If the system voltage drops (lights on at idle) the
current will also be reduced. Any change of current will affect the flash
rate of the turn signal flasher unit, but will not affect flashing of the
emergency flasher unit.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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