Oddball indicators.

[57traveller]

Yesterday I noticed that the indicator stalk warning light wasn't working on my saloon. On arrival home checked and all indicators were working. Must be the warning light bulb! Removed and tested found o.k. but fitted new one anyway. Tried indicators, all working but warning lamp only working for left turn.
Flasher unit? Didn't have a spare so fitted good unit from Traveller which has done the trick. However, as the supply to the warning lamp (light green) is the same irrespective of which direction the switch is moved can't figure out why replacing the flasher unit has cured the fault? Also as all the indicator lamps were working correctly the current must have been flowing as it should through the direction switch.
Any ideas?

[Cam]

I've had this. The flasher unit is a 3 prong unit. The 3rd prong (middle I think) switches the warning lamp, so if it has a dodgy connection inside the flasher unit it will stop working while the indicators work fine.

I replaced mine temporarily with a 2 prong mini unit and it worked fine except there was no warning lamp lit.

[Willie]

Yes, I have this problem at the moment. I have fitted a warning
buzzer to my car as it has non self cancelling flashers and the buzzer
is not being operated reliably even though the flashers are working
perfectly. The fault is in the flasher unit.

[57traveller]

Yes the "P" connection feeds the warning lamp. But the flasher unit doesn't know or care which indicators the switch connects to. It just has feed from fuse box and output to switch (L and B) plus warning lamp separately. So if the warning lamp works for one direction (in my first post), proving the output from "P" and earth after warning lamp are correct, it should work the other way. I know the circuits for both sets of indicators are fault free because they work.

[Cam]

So... you know how they work and that it has a separate connection for the warning lamp, but you can't figure out why changing the unit over has made any difference?

I must have missed something... surely if both units work fine for indicators but one does not operate the warning lamp then its warning lamp connection must be dodgy inside?

[57traveller]

Cam - there is only the one warning lamp connection inside the unit irrespective of which way the indicator switch is positioned. If the warning lamp works for one direction then it should work for the other. That is what was happening and I can't figure out why changing the flasher unit cured the fault if the warning lamp was working anyway but only for one direction.
Fortunately changing the flasher unit did sort the problem and logically that's what was causing it, but it's figuring out why.
What I didn't do and should have was try the old unit in the Traveller but I took it apart to see what made it "tick"!!! I didn't damage it so I might have a rummage in the dustbin and just try it? If the same fault is apparent then it was the flasher unit, if not then I've done something to cure the fault, but if that's the case I don't know what.

[Cam]

Ah right, I thought I had missed something! I thought the unit was not operating the warning lamp in BOTH directions! But you do quite clearly say that it is only working in one direction in your original post! (wake up Cam! ).

Yes, I see what you mean, it should make no difference at all which way the indicators are flashing to the warning lamp! Very strange. Take the can off and have a look to see what's going on but I doubt there's anything to see.

I bet it's something along the lines of a dodgy warning lamp connection inside the flasher unit that's current dependant, and one side is drawing slightly more current than the other (due to bulb holder corrosion etc). That's the only thing I can think of.

[57traveller]

(wake up Cam! ).

It is Friday after all.

Yes it is odd. I initially checked Haynes wiring diagram and the first thought was it can't happen!! I've removed the can (yesterday) and as you say there's nothing obviously amiss. Quite a clever, simple little device really.
Anyone want a picture of the internals for reference?
I've retrieved it out of the bin - mightwell be o.k. I'll connect it to the Traveller and see what happens
Your last paragraph could be spot on. Initially I'm going to check front and rear lamp holders for good contact, in spite of no fault at the moment, might even be a dodgy bulb(s)?? It'll surely not do any harm. I may even take a look at the switch and check the contacts for muck or contamination - but then again if it ain't broke (at present) etc.

[Cam]

I have taken one apart before (just out of interest) but a picture of the internals would be good for other folks who might be wondering.

[57traveller]

Will do, in due course.

[bigginger]

but a picture of the internals would be good for other folks who might be wondering.

...and very good for comedy value. State of the art electronics 50 years ago

[57traveller]

A lot of modern "state of the art" automobile electronics with a built in destruction factor will not be working in 5 years time never mind 50.

[bigginger]

Too true, but it's still amusing - a combination of 'O' level physics and clockwork alchemy... and if you find a flasher unit that keeps working for the lifetime of a Mog, I'd love to know where!

[rayofleamington]

A lot of modern "state of the art" automobile electronics with a built in destruction factor will not be working in 5 years time never mind 50.

A lot of the modern electronics are 20 times more robust than the old stuff too!
Stuff from the late 80's and early 90's is a very different matter!

I guess the modern stuff gets a bad name as there is 100 times more of it in a new car so it is more likely to fail. If modern cars had the same level of electronics and a classic they'd be more reliable (on average) - but not after 15 years old!
(They could make the stuff last 50 years, but then go out of business as someone cheaper would get the work)

[57traveller]

and if you find a flasher unit that keeps working for the lifetime of a Mog, I'd love to know where!

How about the one I've just replaced then - date stamped 11/72, when I assume the indicators might have been modified from the original flashing brake lights. But it's not strictly outlasted my car! 33 years isn't bad though and it might not actually be faulty.

[bigginger]

I'm impressed - but in my experience, it's pretty unusual for a flasher unit. You sure it didn't come from a Volvo, completely unused?

[57traveller]

You sure it didn't come from a Volvo, completely unused?

No but it's probably lasted so long because like most Volvo, BMW, Mercedes Benz and 16 drivers I never use indicators.

[57traveller]

I suspect Cam's "current dependent" remark was correct. Even with a new flasher unit the same thing eventually happened again. I checked all the lamps and holders and all like new. I checked the switch and the contacts for each side plus the supply contact were very dirty, date stamped on switch body 1/62 so not bad for 43 years. Cleaned these and all was well. However as the switch mechanics are very worn and sloppy decided to fit a new switch anyway.
Now a warning - when changing the switch I must have moved the horn supply slip ring up the steering column slightly and enough for it to be making intermittent contact with the steering wheel. So when driving along the horn was sounding like Morse code! Becoming so bad I had to stop on the road at one stage and disconnect the horn supply. It took a while to spot this. So beware.