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MG Midget and Sprite Technical - Indicators Not Working

Hi All

I have a MKII 1966 positive earth midget that i am putting back together.....

The Indicators are not working at all. I have checked the bulds and all ok, the side light are working so the earth appears to be good enough. I have also tried 3 different flasher units the old one and two new ones but still no joy.

Does anyone have any ideas how I can fault find the wiring or give me some guidance as to where to start as electrics are far from a strong point with me.


Regards

Tony
A Brough

hi tony,

i have just resolved the same problem on my midget, this turned out to be a dodgy hazard light switch which i suspect is not in circuit on the models of your age. i think you will also have a 3 pin flasher unit and not a 2 pin like mine but the principle is still the same. marked on your flasher unit should be B, L and possibly P. the 1st thing to check is that you have 12volts from ground to the B terminal when the ignition is on you can pull the wire which should be the all green one to check if the power is coming down the line, if you do not get a voltage reading check the output from the fuse box with all the green wires attached. If you do have the voltage on the B terminal/green wire then your problem is possibly on the indicator switch or connections from the switch to the indicator lamps. as a quick check of that circuitry you can connect a lenth of wire to a known negetive source in a positive earth case (the battery being the best) then pull the light green/brown wire off the L terminal of the flasher unit and connect it to the wire you have to the made negetive, then when you operate the indicator switch the direction lights should come on solid for which ever direction you have the switch in. if they dont then get access to the switch terminals and you should see 3 wires (5 if you have a 3 term flasher) you will only be interested in the light green/brown, green/red and green/white. put the wire from the negitive source on the green/red and the left hand indicators should light up, and when you put it on the green/white wire the right hand indicators should come on. if they dont then the problem will be at the connectors where the circuit splits between the front and the back of the vehicle, im not sure where these connecters are because i didnt need to go that far when assessing my problem.
i hope this helps and let me know how you get on with it or if you get stuck at any point.

dave
da cook

Hi Dave

Thanks for this

I have worked through to this point
>>>>>
as a quick check of that circuitry you can connect a lenth of wire to a known negetive source in a positive earth case (the battery being the best) then pull the light green/brown wire off the L terminal of the flasher unit and connect it to the wire you have to the made negetive,

then when you operate the indicator switch the direction lights should come on solid for which ever direction you have the switch in.
<<<<<

The light comes on solid but I dont understand where to go next as if this didnt happen you said to go to the switch, but I cant see what to do next if it does happen.

Sorry I may just be being a bit thick ?

Regards
A Brough

"I have also tried 3 different flasher units the old one and two new ones but still no joy."

A number of times I've got faulty brand new modern car electrics components, infact twice on different cars indicator flasher units

So just a suggestion, if we assume the old one is broken that leaves the two new ones which could also be faulty - if you can borrow or buy a second hand/used or NOS I'd give that a try before going further

Or you could as a process of elimination try all three units on a positive earthed English car with working indicators if someone nearby can help out with this

I could be wrong of course in this case but (when I remember and where possible) I always test compoments as much as possible before fitting them now
Nigel Atkins

ok if the lights came on solid when you when you connected the wire from the battery to the light green/brown for which ever way the indicator switch is and you had a full 12v on the green wire then i would deffinatly say the flasher unit is faulty. you can confirm this by directly connecting the light green/brown wire to the green wire and then with the ignition on operate the switch and the direction indicators should come on solid.
the function of the flasher unit is that the circuit is connected internally until a bi metal strip warms and breaks the circuit, it then cools to remake the circuit then it warms again etc etc to create the flashing effect. i think these units are are fragile when connected the wrong way round and fry the internal circuitry so take care to ensure that the green wire connects to the B terminal and the light green/brown goes to the L terminal. im not sure if because your car is possitive earth whether you need a special flasher unit as the current will certainly flow in the opposite direction, but the diagram in the book still uses the same connections for both types of earthing.

dave
da cook

hi again tony,

it may also be worth considering converting back to a negetive earth vehicle, going through all this with you reminded me of the time when poss earth cars were popular but whenever i had one i used convert it right off because it was a pain fitting things like radios and finding ways to isolate them, there was also lots of talk at the time that poss earth cars corroded quicker due to electrolisis so this may well be worth consideration.

dave
da cook

As usual on rereading my post I see I've not been very clear

I had a Triumph with a faulty flasher unit so I bought a new one from one of the large classic parts suppliers, the new one didn't work either, another owner gave me me a spare old unit he had, it worked fine

When I picked up my present Midget the flasher unit played up despite being a new unit (it certainly looked new and very cheaply made) so we swapped it out with another used unit which was working on another car and it's still on my car now working fine
Nigel Atkins

Hi Dave and Nigel

thanks for your input.

I have ordered another flasher unit and will let you know how I get on with it.

I have considered changing the car to Negative earth, but I want to get a few other things sorted first.

Thanks again

Tony
A Brough

Cheers Tony, do let us know how you get on

If you see a s/h working or NOS unit I'd suggested getting it just in case - or you could pass it on like some kind person did for me
Nigel Atkins

I had exactly the same problem on my 73. The signals did not work and I traced it to a green/brown wire which connected to the hazard light switch. One wire pin was broken and I had to replace it (had pulled out from the backshell). Moss did not sell the pins so I managed to use a mollex pin that I had to widen slightly. I crimped and soldered it. Now my signals work.

Rebecca
R Harvey

Thanks for all the help.

I managed to get hold of a different "winky Pot" and things started to get better. The back plate on the nearside was a bit ropey to say the least and for some reason when both the bolts to secure it to the wing were tightened it would make the side light flash instead of the indicator.... I tried cleaning al the connections and double checked the wiring, but the only way I could get it to work was to slacken off the one bolt.

Anyway I bought a new backplate and all is now working.

Hoping to get her mot'd this week so I can start to enjoy the summer before starting more work in October November time.

Thanks again

Tony
A Brough

ummm, I didn't think of that - I should have as I'm just about to change the whole side/indicators light assemblies as one has rusted badly on the backplate because it had a hidden break in the glass lens

The other backplate is starting to rust too so two new units before the waxoyling

They must start rusting quite quickly
Nigel Atkins

This thread was discussed between 17/06/2010 and 25/06/2010

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