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MG Midget and Sprite Technical - Indicators

This is driving me mad ! The old indicator arm collapsed so I'm fitting a second hand replacement. The cables and colours don't quite match up but following the Haynes wiring diagram, I've got to the stage whereby all the indicator lamps will switch on, left for left side and right for right side together with the dashboard repeaters. I'm using a new (two pin ) flasher unit and even tried an older three pin flasher unit but although all the appropriate lights come on , they won't flash!!.
All I get is a muffled "click" from the flasher unit.
I've tried leaving it on for up to 5 seconds but I'm wary of leaving it longer in case it burns out.
Any insights would be gratefully received.

Malc
M J Chapman

I had a similar problem a few years back. Mine was caused (I think) because the unit was a 47Watt (intended for a car with 2 x 21w + a 5w repeater) which coupled with the imperfect connections in the wiring to the bulbs, was not quite enough current draw to operate the flasher unit.

In the end I found an old 42Watt unit, and used that and its been fine ever since.

I don't think you will cause any damage if they don't flash, but of course it does need to be sorted.

Jim
J Smith

Thanks Jim. I thought there might be insufficient current going through the unit, so I cleaned all the bulbs and bulb holders. Also the older 3 pin unit flashed on the bench with just one 25W bulb, albeit rapidly.
Maybe I'll try and measure the voltage at the bulb holders to see if there is high resistance somewhere in the bullet connectors.
M J Chapman

Modern flasher units can be rubbish, have you got the old one to put back in?

Which car are you working on (the7/68)?

And did you mean 25w bulb?

If you have the original two pin then Lucar post marked B takes the green wire from fuse box and Lucar post marked L takes the light-green/brown wire to switch.

I have a spare working (s/h) Lucas 8FL Type 36 35048B (not A), made week 23 of 1981 and two holders, one new but not concours and other s/h so if you're stuck let me know (same as below but that was made in week 51 of 1985).



Nigel Atkins

Update - Finally, I noticed that one of the flasher lights was coming on at the same time as the side light!
Further investigation revealed a partial short (to ground) in the side lamp bulb holder. It appears this had drawn too much current, got too hot and caused the indicator lead to fuse with the side lamp lead, where the two wires touched. So after replacing all suspect wiring and re-soldering the side lamp holder central contact,the indicators are flashing ! Yes! Result!
Malc
M J Chapman

Well done and good spot.
Nigel Atkins

"..Modern flasher units can be rubbish, have you got the old one to put back in?.."

Frogeye up for MOT last Thursday - Northern Ireland's lack of a legislature means no exemptions yet.

Anyway, (Lucas?) flasher unit died on the way to MOT, so failed on this one fault. Checked wiring out when I got home and unit definitely deceased. Totally different unit in the Elan so no chance of a quick fix.

Next morning was pleasant and as Virgin were creating traffic chaos in town burying fibres I walked to the Motor Factor's (one hour round trip walking) for a replacement.

Replacement (Durite??) dead on arrival! So another long walk, plenty of exercise that day. Second replacement (no maker stated) finally working. Re-test next Monday.

Dennis




D Stanfield

Dennis,
if your pre-MoT flasher was Lucas I'd have thought (don't know for sure though) that it would have Lucas on it somewhere, they seem to last many decades of use unlike the modern ones which seem to last minutes, hours, days or weeks.

If you take it apart it will soon be obvious if it "vintage" or more modern made. The following is from Paul Hunt's excellent mgb-stuff website but will give you the idea - http://www.mgb-stuff.org.uk/flashers.htm#ind

Green box Lucas product (not always as good as the older made units, but don't know with flashers) - https://www.autoelectricalspares.co.uk/lucas-sfb100--35010-fl5-flasher-unit-gfu101-gfu2101-1179-p.asp
Nigel Atkins

I fitted one of these:

https://www.ebay.co.uk/itm/12V-ELECTRONIC-INDICATOR-FLASHER-RELAY-CLASSIC-CAR-WITH-OE-CLICK-X-L-P-2-3-PIN/181922797997?hash=item2a5b7199ad:g:FMsAAOSwjtZbvOxZ

Works with filament and/or led bulbs. Constant flash rate, flashes the remaining light if one of them fails. No more rubbish Lucas stuff. What's not to like? (other than the look of it)
Simon Wood

Nigel,
The first failing unit was fitted about eight or nine years ago, no makers markings but I seem to recall seeking out a Lucas part at the time. But was probably a modern junk part that lasted a few thousand miles. First replacement was marked Durite and was a piece of junk. Second replacement has no maker markings but looks much better made and works, so fingers crossed.

D Stanfield

Dennis,
so you've gone electronic then?

Paul's not so keen on them as he reports that they don't tell you when a bulb has blown but I was happy with the one I fitted, steady flasher rate even at idle, good for when your sitting in the middle of the road waiting to turn.

I've suffered from so many piss-poorly made modern parts that I'd guess that if you can get original NOS, depending on how new the NOS is, then those parts are generally the better ones. Often used parts can be good.


Nigel Atkins

Nigel,
Not sure whether the new flasher unit is mechanical or electronic, the guy in the parts shop, who is also into classic motors, just said "try this one".
I rewired the car some years ago and used a two pin flasher unit so is non-standard in that respect in any case.
D Stanfield

Dennis,
as long as it works it doesn't really matter. A possible way to tell is with the mechanical when the indicator is on the lights might go slower at engine tick-over than at higher revs but remain at a steady speed with electronic.

With the mechanical if a bulb goes it flashes much faster which gives you a warning of the fact whereas I think this doesn't happen with electronic but I've never tested this.
Nigel Atkins

Well would you believe it? Well you probably would when I tell you the new flasher unit has just failed!

I prised the mechanism out of the can and the braided wire was no longer connected to the moving contact.

It appears that it should have been attached by a miniature spot weld but it looked like only one tiny strand had been "caught" and that was why it went ok for about an hour and then conked out.



M J Chapman

However, all was not lost as I managed to solder the connection back again and I found that the flashing speed could be adjusted by careful bending of the fixed post.
Then just when I was satisfied all was well and was pushing the can back into the clip, one of the spade terminals broke off!!
Oh the joys of classic car ownership!


M J Chapman

That looks old style, I might be wrong but I think the really modern ones might be more like a bit of tinfoil inside.

Interesting about the flashing rate adjustment, I'd set it a bit faster to allow for the rate slowing at tickover revs.

You're lucky this part has been repairable, is easy to take off and dissemble and easy to put back on, I can't think how many hours I've lost in only the last month with replacing faulty parts and even more annoying is repeating some work as different new parts fail at different times. I don't usually have to worry about fitting being seized on, I might as well use wing nut on some areas. - Joy it ain't.


Nigel Atkins

This thread was discussed between 27/09/2018 and 13/10/2018

MG Midget and Sprite Technical index

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