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MG MGB Technical - turn signals

Hi everyone, my turn signels won't flash. fourway flashers work. looking for the flasher unit for the turn signels. my clymer shop manual says that it is next to the fuse box. not so on mine. there is a small silver unit on the pass. side w/two wires going to it one is dark green and the other is light green/with a purple trace line. i failed to mention that i took down the speaker cover and it is mounted on the shelf near the fire wall. hope i didn't confuse to many. Not good with wiring. ANY help would be GREAT. iknow going to someone will get exp. Thanks to all. Don Baker
don/deb baker

I'm having the same problem ... also my heater blower isn't working.

I have a *right-hand drive* 1980 GT. My flasher units (both of them, turn and hazard) are in the passenger compartment close to the steering column. I have power to the hazard flasher unit but not to the turn flasher.
Geoff Everitt

Don/Deb, what year car? RAY
rjm RAY

Geoff, sounds like the inline fuse that supplys those two circuits has died (or bad connections around it).
Look in the engine bay very near the main fuse box, you'll see a couple of inline fuses with white/brown tracer feeding a green circuit.
One supplys the cooling fan and one supplys the turn signals/heater and provides a 12v to the tach.
The white/brown that supplys the problem circuits comes from a piggy-back connector on the ignition relay, which is another area where corrosion etc could have set in and hurt the circuit.

The Haynes diagrams for this year are wrong in this respect, as they show a subdivision of the white circuit feeding both the inline fuse and the coil etc, this (at least on my 77GT and it looked 'factory') was not how it was at all and confused me as I was re-wiring for my V8 conversion.

All of this information may or may not be of any help to non home market rubber bumper owners too, not sure.
RoadWarrior

If it's a fuse, then depending on year tach, wipers, heater, brake lights, reversing lights and so on won't work either.

If they light but don't flash then it isn't a fuse of course, but either *is* the flasher unit, or a high-resistance connection anywhere from the battery to the turn switch. Installing a new flasher unit may well appear to fix the problem, only for it to happen again. New flashers don't mind a bit of resistance, but once they are burnt in suffer from the same problem. The lazy way is to fit a modern 3-pin flasher (earthing the third pin) as they are not so sensitive to resistance, but the proper way is to find and fix the real problem by measuring voltage drops through the circuit. If you have hazards the hazard switch itself is often the cause, as it is usually rarely used and the grease inside hardens to become an insulator.

77 seems different to 80 with regard to the wiring of the coil and ignition warning light, so don't be too hard on Haynes, which *is* correct for an 80. The easily identifiable difference seems to be two inline fuses below the fusebox both with white/brown and green wires (albeit on opposite sides) for the later case but only one inline earlier.

Non-UK cars are different again, but similar to the 77.
P Hunt

Thanks for your suggestions chaps!

I clearly have a dodgy connection somewhere. By doing nothing in particular, they somehow started again this morning. I went out for a wee drive ... after working correctly several times, all of a sudden they didn't.

Back home this afternoon, they started again when I lifted one of the bundles of wires near the steering column. I was about to tape the offending bundle into a "good" position but, when I retuned with the tape, I couldn't find a "good" position. Incidentally, the fan also worked for this short time.
Geoff Everitt

Thanks to all for the help. what i found was that after a new radio was installed the tech used a wire from the cig lighter which was some how conected to the single lights. like i said i'm not good with wiring. my B is a 71. i followed wires,cleaned connections,checked plug ins taped,wire ties now they all work. i don't know if what i did was the answer but time will tell. It's a MG. Thanks to all. Don Baker
don/deb baker

This thread was discussed between 30/01/2010 and 14/02/2010

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