Trailer lighting issue - indicator double speed when brakes or side lights applied - ground issue?

[dcShadow]

Hello all,

Appreciate that this isn’t specifically a caterham issue but my hope is that someone else has experienced and solved this issue. 
 

Trailer is an eco-trailer with LED indicator and brake/side light stacks.  Car is a BMW but also experience the issue with the VW camper (which tells me it’s trailer at fault)

indicators work fine when they are used in isolation (no brake or side lights) - but yes, when the brake is applied or the side lights are turned on then a fault appears on dash and the indicator flashes at double speed (like it would in the old days with a blown halogen).  Interestingly they flash when hazards are on and brake/side light enabled.  

Replaced trailer connector and also ran a multimeter across the terminals - no shorts or unusual resistances as far as I can see.

Any immediate ideas ?

 

DC

[SM25T]

Usually an earth missing, so one circuit is routing through another bulb.

[Jonathan Kay]

24 minutes ago, SM25T said:

Usually an earth missing, so one circuit is routing through another bulb.

That's where I'd start.

You can pull bulbs one at a time and see which one makes a difference.

And use an additional lead to provide a temporary good earth and ditto.

Jonathan

[dcShadow]

Seems it’s the LEDs potentially - not enough load for a typical trailer circuit. 
eco-trailers have the following - https://eco-trailer.co.uk/product/smart-load-relay-resistor-13-pin-plug-in/

bought and will see if it sorts it. 

[Jonathan Kay]

It's often necessary to replace the timer/relay when changing from incandescent to LED indicators. But I wouldn't expect that to account for the effect of the other light circuits.

Jonathan