Brought some LED tail lamps for the trailer.

Installed them, along with relays and the bulb failure alarm on 7-pass relay isn't working on the indicators, as per legal requirements :bang:

Wired resistors on +ve side of the indicator feed in-line. Is this correct?

I believe it is, but the ebay seller is as about as much help as a blown light bulb

Thanks in advanced.

Can I clarify your post for others.

Two points:

1) I was not aware that vehicle/trailer ANY bulb failure was a legal requirement. The only requirement is that that when the indicators are operated AND a trailer is attached then there should be an audible repeater sound, which should cease if a trailer indicator bulb fails. I know this is what you meant to say but I thought would clarify this for others.

2) As per custards post you may need a dummy load in parallel with the LEDs. Most 7 way bypass relays I've seen actually feed the indicator light/load via a diode and then measure the voltage drop (0.6V) across the diode to trigger a transitors to sound the audible repeater alarm. I'm guessing that your leds take 20mA to 100mA (or more) but not the 1+ Amp a normal indicator bulb would take. However any diode with 20+mA flowing through it will give a diode voltage drop which would be recognised on units I have seen.

I can only assume that your bypass relay uses an alternative current measuring system and is looking for higher current loads.

A dummy load will always trigger the audible warning and if the LEDs fail you won't know.

Your first point was indeed what I ment

It is a requirement isn't it

2nd point, I see what your saying, but plan on having the resistors just before the LED units, so short of the units themself failing all should be ok as if I get a dodgy connection before the Resistors then the audable warning should stop. If its a failure after the resistor then I'll soon find out when checking the lights, and should they fail in journey then 'oh well' so to speak. I'm confident they won't but even if they do, won't be much different to the majority of trailers out there

Most Easterly Pandas said:

It is a requirement isn't it

Click to expand...

Yes, but for indicators only. The requirement is "audible repeater" when driving trailer indicator lights, as opposed to bulb failure warning. Mute point because a trailer indicator bulb failure would not trigger the audible warning.

A bulb failure warning, like many cars have for their lights would not meet the "audible repeater" criteria.