[Mgs] Mix n Match

PaulHunt73 paulhunt73 at virginmedia.com
Mon Apr 18 01:57:08 MDT 2022

The 3-pin flasher was only used on Mk1 cars but the 4-fuse fusebox 
didn't start until the 1970 model year.

The flasher unit should have 12v on the green and light-green/brown 
wires all the time the ignition is on, as well as the common contact of 
the indicator switch.  This lights the lamps as soon as the stalk is 
operated, then the turn flasher 'warms up', clicks and turns them off, 
then further clicks turn them on, off, on, off.  The hazard flasher 
works the other way round i.e. when first operating the switch nothing 
happens for a moment, then after a pause there is a click and the lamps 
light, then further clicks turn them off, on, off, on.

Where hazards were factory provided the 12v ignition feed to the turn 
flasher does go though that switch, and is disconnected when the hazards 
are switched on.  That's to prevent voltage feeding back through the 
turn flasher onto the ignition, including the fuel pump, when the 
ignition is off and the hazards on if the stalk has been left operated 
to one side or the other.  When rarely used the grease inside the 
hazard  switch goes hard and becomes an insulator rather than a 
lubricator, and can affect the hazard lights as well as the turn 
signals.  Sometimes flipping the witch back and fore can restore things, 
but in my case I had to open up the switch, dig out the old grease and 
replace with fresh, and it has been fine ever since.  The original UK 
rocker switches do lend themselves to doing that, can't speak for the 
American switches.

For me the puzzle is still why something was clicking when the lights 
weren't working.


On 18/04/2022 00:32, Michael MacLean wrote:
> I'm confused. (nothing new) in trying to get my turn signals working I 
> checked the wiring diagrams out for the early and late MGs.  In the 
> wiring diagram for the early cars it shows a 3 pin flasher relay with 
> a two fuse unit.  In the late MG wiring diagram it shows a two pin 
> flasher unit and a four fuse unit.  Looking at my car (a 69) it has a 
> two pin flasher unit, but the car has a two fuse block unit.  What the 
> heck?
> Mike MacLean
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