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flasher relay


HWade

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I have fitted indicators to a vehicle that came in for work, and i have had an issue with a relay. The relay is flasher 3 pin type. Pin Numbers being 49, 49a, 31. I have wired it up, but wiring it as per the instruction the dash light stays on. Could some one help please. heres a pic of a diagram. Ignore the wires that are marked E flasher relay and E flasher switch. These are hazzard. Thanks

relay diagram.jpg

Edited by HWade
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I have tried different ways but no joy, yes the indicators do flash. Richard if i put it across both left and right wont this make all the indicators come on at the same time. Ive tried to have the dash light inline on the earth but no joy. Cant think where i am going wrong, unless a faulty relay.

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Ah, the advantages of age ( there aren't that many, to be frank < oops - sorry for mentioning Frank ...>)

 

Right, two things, since I remember the legacy Lucas units that these replaced;

 

1. 31 Earth

2. 49 Positive feed from fuse block

3. 49A Switched feed to flashers via indicator switch

 

If this is how you have wired it, and it doesn't work, then you have either too much (unlikely) or too little wattage load on it.

 

The originals would not start to flash until they had at least 21 watt draw and would not hit the correct flash rate till they had 42 watt draw. I'd guess you have just wired the dash indicator switch and didn't have enough wattage draw.

 

Checked that lot and it still doesn't work? You have fried something - bin it.

Edited by Gordon_M
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Howard

 

One gang of the indicator switch should be between 49a and the left or right bulb - the dashboard light is on the other side of the switch nearest the indicator unit and also connected to 49a; see the 3-terminal version of the circuit at: http://www.netlink.net/mp/volks/htm/signals.htm

 

Also note that some sources suggest connecting the dashboard bulb from the fuse (+ve) to 49a - I think this facilitates dead bulb detection as the path to ground is via the indicator bulb.

 

HTH

 

Iain (who was once an electrical engineer!)

Edited by g0ozs
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Howard

 

Richard's suggestion of putting it across L and R (on the indicator bulb side of the switch) is sound, as only one bulb is powered and the resistance of the dashboard bulb is much higher than that of the unused indicator - so the unused indicator just functions as a path to ground and does not get enough power to be illuminated. This approach is perhaps less good for dead indicator detection as it will only detect a failed L bulb by failing to flash when indicating R (or vice-versa); the recommended circuit as per the VW diagram uses the bulb currently active as the path to earth.

 

Regards

Iain

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Chris

 

The DIN circuit labels are decoded at: https://en.wikipedia.org/wiki/DIN_72552 - here are the ones for indicators

 

[TABLE]

[TR]

[TH=colspan: 2]Turn indicators[/TH]

[/TR]

[TR]

[TD]49[/TD]

[TD]flasher unit in[/TD]

[/TR]

[TR]

[TD]49a[/TD]

[TD]flasher unit out, indicator switch in[/TD]

[/TR]

[TR]

[TD]49b[/TD]

[TD]out 2. flasher circuit[/TD]

[/TR]

[TR]

[TD]49c[/TD]

[TD]out 3. flasher circuit[/TD]

[/TR]

[TR]

[TD]C[/TD]

[TD]1st flasher indicator light[/TD]

[/TR]

[TR]

[TD]C2[/TD]

[TD]2nd flasher indicator light[/TD]

[/TR]

[TR]

[TD]C3[/TD]

[TD]3rd flasher indicator light[/TD]

[/TR]

[TR]

[TD]L[/TD]

[TD]indicator lights left[/TD]

[/TR]

[TR]

[TD]R[/TD]

[TD]indicator lights right[/TD]

[/TR]

[TR]

[TD]L54[/TD]

[TD]lights out, left[/TD]

[/TR]

[TR]

[TD]R54[/TD]

[TD]lights out, right[/TD]

[/TR]

[/TABLE]

 

A much more authoritative source is the single-circuit test circuit in the Hella catalogue/databook at: http://www.hella.com/hella-ae/assets/media/HMEA_Relays%20and%20Relay%20Devices.pdf on page 36.

 

Internally the flasher unit has a relay or transistor switch between 49 and 49a (prehistoric Lucas units had a bimetal strip thermostat that heated up due to the bulb current to break the circuit hence the dependence of flash rate on load!). The ground 31 is only for the internal workings of the flasher unit and the bulb current leaves 49A, through the indicator switch to ground via the bulbs. See example internal circuits at http://cdn.instructables.com/FFW/PL59/GU4HW87K/FFWPL59GU4HW87K.MEDIUM.jpg (a 2 terminal unit with only 49 and 49A) and http://mgaguru.com/mgtech/electric/et104.htm (B and L are 49 and 49A, P would be a C terminal in DIN coding)

 

Iain

Edited by g0ozs
added note on flasher unit insides
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(prehistoric Lucas units had a bimetal strip thermostat that heated up due to the bulb current to break the circuit hence the dependence of flash rate on load!). Iain

 

 

I used the prehistoric ones all the time, and very nice they were :D

 

When the 6 volt units vanished from the shelves, you could get a 12 volt unit and shorten the bypass wire coil by about half, and it would then work very nicely on 6 volt.

 

Electronics - hah !

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Gordon

 

I remember playing with salvaged ones as a boy and taking them apart to see what was inside - but I belong to the time when there were electronic ignition projects in the like of "Practical Electronics" and "Wireless World" so all solid state for me ..

 

Iain

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The trouble with original bimetallic units was that the bulbs didn't come on until after the strip had heated up, so there was a delay before the indicators were seen.

 

Andy

 

Sent from my SM-T310 using Tapatalk

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