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MG MGA - Flasher Unit

My current flasher unit is on its way out with very slow and erratic flashing, but providing all the correct lights. I went to my local motor factor yesterday and bought the correct one for the MGA. All the lights flash strongly and correctly except for no light at all in the warning jewel. I put the old flasher back on just to check the bulb integrity. It worked fine. I then looked at the instruction leaflet written in poor Chinese English and from what I could understand it said the warning light spade terminal (P) on the unit is positive earth. My car is negative earth. I did not think the flasher unit was earth sensitive? Or have I just got a duff unit?

Steve
Steve Gyles

The flasher unit isnt polarity sensitive Steve, changing polarity may possibly reverse the indicator sequence (Left flashing first before Right for example, but otherwise it works the same.
You probably have a faulty unit.

You could always wire it up off the car to test it, or just buy another make and try that.

Colyn
c firth

Colyn

That's what I thought for the correct MGA flasher. Perhaps this Chinese version is a wolf in MGA clothing and does require +ve earth; who knows. Got my money back. Will now source from a standard MGA supplier.

Steve
Steve Gyles

Why not just fit an electronic flasher unit.... or is that heresy? Much less sensitive to variations in resistance in the circuit affecting the flash frequency.
Graeme Williams

The Chinese unit may have some electronics in there, which are likely to be polarity sensitive.
Dave O'Neill 2

I found the new "lucas" flasher to slow.
I carfully opened it up and replaced the innards with a electronic flasher guts.
Looks original and works the dream.
Bruce Suelzle

I think the electronic ones are polarity sensitive.
Graeme Williams

I have a box full of used flasher units, as I don't have much faith in modern replacements.

I do have a tendency to hoard used parts!
Dave O'Neill 2

You might try a NAPA #550, if it's available. It solved my turn signal problems last year. 12v.neg ground. Marvin,ct
Marvin Stuart

I had the same exact problem. Throw out the innards and keep the canister. I put new new inards from local auto parts store. What a waste of time trying to figure out a badly made unit.
Lmazoway

Most modern flasher units require an additional earth connection to function, tho I have seen a few that use the fixing screw as an earth.


It sounds as if it's working ok but is a faulty unit, ie no pulsing live out of the "P" connector.



I usually use a Lucas SFB163 which fits old Renaults and works well.


It's marked 31................which is the additional earth.


49 which is live, ie green


49a which goes to the dash switch, light green/brown.



C which is the pilot lamp, ie green,/purple.



Hope that helps
SR Smith 1

My new Moss flasher unit lasted about three months before dying. I was able to replace it with a 62-67 MGB flasher unit from my local NAPA store which worked fine except it was missing the top mounting tab. I have since bought another MGA flasher unit but I'm keeping the NAPA one for a spare.
Larry Wheeler

I've suffered from unreliable flasher units over the years. The normal pattern is for the indicator flashers to work but quite early on the jewel stops working which is the position I'm in now. Sometimes when I rev up I can get the jewel to work and I wonder if it's sensitive to volts drop?
J H Cole

My jewel did same. Worked after I wiggled the bulb in its holder..
H L Davy

This thread was discussed between 29/07/2015 and 25/08/2015

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