LED Flasher unit?

[CovKid]

What is the problem with using a 4 pin led flasher unit like these? http://www.ebay.co.uk/itm/4-Pin-Car-Mot ... SwgZ1XtXp0

Sadly pins not in right places though would in theory work with modding I suppose.

Have a look at 'LED AUTOLAMPS' website. they do a 3 or 4 pin relay specifically for led lamps.
might be what you're looking for.

Autolamps page here looks like it might be correct one: http://www.ledautolamps-uk.com/en/produ ... oprocessor" onclick="window.open(this.href);return false;

£20 here: http://www.whiteboxuk.co.uk/i-ls-relay- ... 2968-p.asp" onclick="window.open(this.href);return false; - undoubtedly correct one - just compared to my 4-pin. However, for correct fault detection it has an extra microprocessor (further £11) so not a cheap relay solution by any means.

Have ordered a 3-pin already which matches stock ones sold VW Heritage etc - will see what happens without pin C2 I suppose

[cassandra]

Hi, having looked at the wiring diagram for the flasher circuit there is one issue that has not been mentioned yet. The flasher warning light gets its earth thru the bulbs when the flasher relay turns the lights off so the warning light is on when the bulbs are off and visa versa. This is obviously not a problem with normal bulbs but as LEDs require so little power they will probably stay on when the relay is 'off' so instead of flashing properly you will probably get a slightly dimmer light when they should be off, effectively a bright /dim rather than an on/off which will upset the MOT tester for a start. The simple answer to this problem is to cut the feed to the warning lamp and make it an earth instead though I would suspect that is easier said than done, and this would mean that the warning light is lit when the flashers are lit.

As far as flasher units are concerned I think the C2 terminal is related to trailer wiring though possibly only if you have factory fitted towing electrics and the 31 terminal is just an earth because the factory flasher unit needs an earth. An aftermarket two pin relay has no earth because it doesn't need an earth. A standard flasher unit will flash too fast with LEDs due to insufficient load on the unit as it is designed to flash fast to indicate that a bulb has failed. This is part of the UK vehicle construction and use regulations but is not checked on the mot as that would involve removing a bulb or disconnecting a lamp which is not allowed, however the flash rate is checked and should be between 60 and 120 per minute although most vehicles are nearer to 60.

[marlinowner]

Construction and use regulations say that indicators MAY flash at a rate outside of the 60 to 120 per minute range if a bulb has failed, not that they have to. Nothing in the regulations about a requirement to warn of a bulb failure.

[CovKid]

Thanks for your thoughts on this. I guess it explains why the LED Autolamps solution is a two-part thing with both a relay and a separate microprocessor required:

"The i-LS Relay has been designed to be used in conjunction with the i-LS Microprocessor, allowing the reliable detection of an LED indicator failure.
The system alerts the driver when an indicator has failed by increasing the flash rate, or terminating an indicator light on the dashboard."

I suppose its a case of weighing up whether the investment is worth it, considering that in normal circumstances my indicators are only on intermittently. The biggest consumption, and far more likely to run the battery down is with engine not running, in hazard mode - a not unlikely scenario. Add up 4x21w bulbs and its quite a draw - 7 amps (on and off).

A pain really as I left my lights on for almost two days as a test and I could still start it as all running lights on mine are LED-based. Indicators are clearly more complicated to get right although even the Gowesty LED indicator kit only shows an upgraded flasher relay - perhaps theirs uses ballast resistors somewhere - something I really wanted to avoid due to the poor efficiency.

This subject has occasionally come up on places like the Samba but not in depth like this. Most grateful. Perhaps LED Autolamp's two-part kit is the only way to do this apart from a complete rethink of the indicator/hazard circuit from scratch, but that then leaves any subsequent owner with a right mess to get their head around - step too far I think. The other possibility is to settle for LED bulbs rather than panels that have just enough draw to not upset the flasher, but nowhere near 21 watts a piece. That could well be the most cost-effective in the end, even if not my preferred route.