Indicator light in speedo problem

[RichC]

hi Brian , whatever happened about this pls?
I have almost exactly the same problem only it occurs on RH indication ONLY & and when the revs have dropped below 1500rpm... I replaced the same things you did & coincidentally nothing changed .. I assume it must be a voltage drop somewhere .
(I'm still on dynamo & control box)

[bcmc33]

hi Brian , whatever happened about this pls?
I have almost exactly the same problem only it occurs on RH indication ONLY & and when the revs have dropped below 1500rpm... I replaced the same things you did & coincidentally nothing changed .. I assume it must be a voltage drop somewhere .
(I'm still on dynamo & control box)

Rich,

I'd completely forgotten about this problem - I simply gave-up as I was never able to see the light, anyway. That's why I fitted a buzzer to tell me that the indicators are working.

[bob_rich]

Hi Brian

Interesting problem! hears my 2p worth. Is you system using a 2 terminal or 3 terminal flasher unit?
on the +2S I have it is a 2 terminal and the indicator lamp is ( electrically) across the terminals of the indictor switch ( stork) when you switch left the indicator lamp current goes through the right hand lmaps because the indicator is a low power lamp (2W ?) the small current in the RH lamps does not produce enough current to light them. In this system if the lamp does not light it would be a funny lamp.

If You have a 3 terminal flasher I believed these have changeover contacts so for the first flash when the lamps are cold the current through the flasher pulls over the contact with enough go to complete the changeover and light the indicator lamp. On subsequent flashes the main lamps will be slightly warmer so higher resistance and while the contacts may open OK for the main lamps to flash it may not make it to the other contact to flash the indicator bulb. On that basis it would be the flasher

whatever I hope its cheap 2 fix!!

best of luck

Bob

[elansprint71]

My indicators work fine but the tell-tale light does not work at all (lamp is OK). This is the one problem I could not resolve when I re-wired my car a few years ago. I gave up fiddling in the end.

What is the recommended buzzer?

[bcmc33]

What is the recommended buzzer?

I bought mine on eBay - it was to suit a motorcycle from this seller: http://www.ebay.co.uk/itm/Integrated-In ... f122776#sf
No connection.

[bcmc33]

Hi Brian

Interesting problem! hears my 2p worth. Is you system using a 2 terminal or 3 terminal flasher unit?
on the +2S I have it is a 2 terminal and the indicator lamp is ( electrically) across the terminals of the indicator switch ( stork) when you switch left the indicator lamp current goes through the right hand lmaps because the indicator is a low power lamp (2W ?) the small current in the RH lamps does not produce enough current to light them. In this system if the lamp does not light it would be a funny lamp.

If You have a 3 terminal flasher I believed these have changeover contacts so for the first flash when the lamps are cold the current through the flasher pulls over the contact with enough go to complete the changeover and light the indicator lamp. On subsequent flashes the main lamps will be slightly warmer so higher resistance and while the contacts may open OK for the main lamps to flash it may not make it to the other contact to flash the indicator bulb. On that basis it would be the flasher

whatever I hope its cheap 2 fix!!

Bob,

I'm sure mine is a 3 terminal flasher unit, so you may be correct. I can't get to see it at this time as the footwell is full of door parts as I am in the process of refurbishing the window frames and rewiring the motors.
However, I've now become used to the buzzer sound to confirm that the indicators are functioning correctly, so there's no priority in my mind for a totally complete resolution.

[RichC]

Thanks Bob,
reallly good to hear from you a lucid account of why it might be happening .
If I were to crank up the voltage from the control box a touch , might this overcome the problem?

[ricarbo]

This one intrigued me, as my recollection was that the three terminal flasher unit has two independent outputs/contacts, one marked 'L' which is connected to the lamps on the outside of the car, and one marked 'P' which is connected to the 'panel' lamp in the speedo. No changeover contact, though. The third connection is marked 'B' for battery.
So I had a look in the Lotus workshop manual. This gives a description of the operation, on pages 98 & 99, also a poorly drawn diagram of the internals (it doesn't show where the battery connection is made). But what it does say is that 'the pilot lamp...will not flash unless sufficient current to...front and rear lamps is passing.' The correct lamps are 21 watt front and rear, with 3 watt for the repeater. This will be 3.75 amps at 12 volts, with an additional 0.2 amps for the 2.4 watt panel lamp (if working!!), proportionately more or less if the battery voltage is different. The circuit is fused, so the current can be easily measured at the fuse block, by removing the fuse and applying an ammeter across the terminals. It's the fuse with the green wires. As usual, poor connections will cause the current drawn to be too little. Being a Lotus, suspicion would fall on the earth connections, initially.
Please excuse my theorising, as I have not had the problem, so have never had to deal with it.
Richard

[bcmc33]

This one intrigued me, as my recollection was that the three terminal flasher unit has two independent outputs/contacts, one marked 'L' which is connected to the lamps on the outside of the car, and one marked 'P' which is connected to the 'panel' lamp in the speedo. No changeover contact, though. The third connection is marked 'B' for battery.
So I had a look in the Lotus workshop manual. This gives a description of the operation, on pages 98 & 99, also a poorly drawn diagram of the internals (it doesn't show where the battery connection is made). But what it does say is that 'the pilot lamp...will not flash unless sufficient current to...front and rear lamps is passing.' The correct lamps are 21 watt front and rear, with 3 watt for the repeater. This will be 3.75 amps at 12 volts, with an additional 0.2 amps for the 2.4 watt panel lamp (if working!!), proportionately more or less if the battery voltage is different. The circuit is fused, so the current can be easily measured at the fuse block, by removing the fuse and applying an ammeter across the terminals. It's the fuse with the green wires. As usual, poor connections will cause the current drawn to be too little. Being a Lotus, suspicion would fall on the earth connections, initially.
Please excuse my theorising, as I have not had the problem, so have never had to deal with it.
Richard

I guees you've found the answer for my problem, Richard. I use LEDs, so there won't be much corrent flowing.

[ricarbo]

Brian, I should like to think I am wrong, because I like LEDs, with their much improved reliability and lower power use. I'm puzzled that you get the right flashing rate using them, as it is supposed to be affected by the load.
But, I think there may be a problem with using them, from a legal standpoint. As I understand the Road Vehicle Lighting Regulations, you are not going to meet the rules. I've had a look on the internet and have copied the following extract:-

11. Tell-tale?(a) One or more indicators on each side of a vehicle to which indicators are fitted shall be so designed and fitted that the driver when in his seat can readily be aware when it is in operation; or(b) The vehicle shall be equipped with an operational tell-tale for front and rear indicators (including any rear indicator on the rearmost of any trailers drawn by the vehicle).12. Other requirements?(a) Every indicator (other than a semaphore arm, that is an indicator in the form of an illuminated sign which when in operation temporarily alters the outline of the vehicle to the extent of at least 150 mm measured horizontally and is visible from both the front and rear of the vehicle) shall when in operation show a light which flashes constantly at the rate of not less than 60 nor more than 120 flashes per minute. However, in the event of a failure, other than a short-circuit of an indicator, any other indicator on the same side of the vehicle or combination of vehicles may continue to flash, but the rate may be less than 60 or more than 120 flashes per minute. Every indicator shall when in operation perform efficiently regardless of the speed of the vehicle.

I understand this to mean the lamp in the speedo will have to work at MOT time and a failure of a lamp has to alter the flashing rate, but I can't see how your arrangement will do this. You could fix the speedo lamp by running it off a relay easily enough,and maybe your audible device might get you over this anyway, but the other part of the rules would be much more difficult to satisfy. I wonder what they do on modern cars with LEDs - presumably a much fancier electronic flasher unit?
Richard

[alexblack13]

Interesting point! My MOT tester lets me sit in my car and operate the lights and flashers etc whilst he checks from the floor. I like this method. Stops ham fistedness direct in its tracks. He now knows the car very well too, and he knows me which helps.

Happy days....

Alex....

[elansprint71]

I rather like the idea of fitting semaphore arms.

[Bruce Crowthorne]

I suffer from the same issue - very frustrating!
I opened up the "can" of the flasher units (I have opened up two so far), a Lucas one and a generic one. A pair of small pliers lifted the lip that holds on the aluminium can.

They both work by having a coil of wire wound round a bi-metallic strip, when current flows, the heat affects the strip and it opens the contacts. The indicators work of one contact and the warning light is operate off another contact.

I tried bending the contacts and had some success (until I overdid it on one unit!).

Currently I use an up to date electronic one - it seems to be solid state (ie no relay) but even that is a bit dodgy as well.

I would love to find a solution to this
Bruce

[elansprint71]

There is a very simple solution:

http://www.flickr.com/photos/joey7/5324827588/sizes/l/in/photostream/

[bob_rich]

Hi (again) Folks

Thought I would add to my earlier post. I looked at my indicator on the seven and the indicator in the speedo does flash in time with the actual indicators so that one is not a changeover as I first suggested--though I have seen some that are changeover in the past-- so must be a slave contact.
First flash being a bigger one still could apply though.

As another post commented most of the flashers are bi-metalic and thus the flashing rate will be affected by battery voltage, cable voltage drops, lamp tolerance and power rating and this does effect the flash rate quite a bit. Its the current through the bi-metalic that determines the flash rate. Modern electronic ones would use a transistor and timing circuit so flash rate would be less effected by the load of the lamps.

On my lads motor bike we fitted LED indicators for the main lamps and fairly hefty resistor were required to take a similar current to the lamps that were being replaced. we had to juggle with the resistor values to get the flashing rate within the MOT limit.

I sketched up a simple way of overcoming the indicator in the speedo not flashing. A couple of diodes and a resistor ( about a quid from Maplins or $2 from Radio Shack) and then the indicator can be powered from the main lamps this would allow any flasher either 2 or 3 terminal to be used. The parts are small and could be installed with some tape or heat shrink in the wiring. Sketch is for -ve earth For +ve earth turn all diode the other way around.

hope that helps cheers

bob