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MG MGB Technical - Dead Flasher Unit

I have recently had to change my flasher unit for the third time due to the indicators ceasing to work. Basically, rather than slowing down or staying lit they did not light at all.

I fixed it by replacing the flasher unit as I noticed that bypassing the flasher lit all the lamps constantly.

However, it wasn't long before it had gone again and now I am on my third in two years.

Does anyone know what might be causing them to go? Alternatively, could the problem actually be elsewhere and replacing the flasher with newer ones makes the problem seem to disappear for a while?

I have looked at the archives and at Paul Hunt's pages and nothing seems to answer my questions.

Thanks,

Alec
Alec

Alec,

I had the same experience, and got fed up buying those sub standard units. I have changed to a modern flasher relay which uses semiconductor electronics for the timing, not a Bi-metal strip. I dont have the wiring details with me, bit the two wires that go to the old flasher are connected to the new flasher, the only thing is you have to make sure the live wire goes to the correct pin, and of course the other goes to the lamps, in addition there is one more pin that must be connected to earth.

Good luck Graham
Graham

Alec,

Dump the old FL8 flasher unit and get a FL19 unit - this has three connectors - one to battery one to lights and one to earth - these units do not depend on voltage like the FL8 and also flash at double speed if one light fails.
Chris Betson

Before you change to a new flasher unit, check the grounds at each light. A bad ground will cause the flasher units to go bad. I know from personal experience. In your case, the new flasher units over come the problem (bad grounds) for a short while, but then over time they burn up. Check your ground wires and replace all the bulbs. Even though my blinkers worked, I found that I had a bad ground on my front right blinker. When I corrected the problem the flasher units stop burning up.
Robert Browning

My indicators have always flashed at double speed since we owned the car (3 years). But all the lights work. Can I still have a bad ground somewhere, or is the flasher unit bad? Don't know what flasher I have. Never looked too hard to find it.
Mark R.
'77B
Mark Rotsky

Mark, Yes, a bad ground would cause the flasher to blink at different or at a fast pace. On my blinkers, the right side blinked slow and the left side blinked at double the speed. I went through every light and every ground connection and found several problems. Now they blink at the correct speed, and evenly, and I have not had any more trouble with my flasher units. Feel free to email me if you want more information.
Robert Browning

Thanks for all your advice chaps. I will check the earth connection tonight and probably go for an uprated flasher this time.

Best regards,

Alec
Alec

HI GUYS JUST HAD THE SAME PROBLEM,THINK MY FLASHER UNIT GONE WEST ,BUT I AIN,T GOT A CLUE WHERE TO LOOK FOR IT

CAN ANY ONE OFFER A LITTLE ADVICE TO A NEW OWNER
BRYAN COOPER

Hi Bryan,

I don't know about yours but mine is below the dashboard, more or less directly below the steering wheel, slotted into a little metal clip which is screwed to the bulkhead. Mine's a rectangular unit, about 1cm x 2cm x 3cm with two connectors ('72 roadster).
Alec

Bryan,
What model is you MG? On my 70 B, flasher unit is behind center console screwed to the frame of the dash.
Gary Mills

A bad ground causes the standard flasher to flash at a *slow* rate or not at all, and it will not cause the flasher unit to burn out as the effect is reduced current through the unit. A partial short to ground (or some other cause of an increase in electrical load) will cause rapid flashing and possible burn-out. Replacement units can be pretty poor these days, two bad replacements if from the same source with the same date code (low turnover) is quite possible. Whenever you fit a non-standard flasher always disconnect one lamp and confirm that you do get a visible and audible indication either by non-flashing (like the standard unit) or double-speed like modern units. Some aftermarket units are no more than hazard flashers which flash at a relatively constant rate regardless of the number of bulbs.
Paul Hunt

This thread was discussed between 19/06/2003 and 25/06/2003

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