Defender LED lights problem only with trailer electrics

Would welcome any advice.

I have a 1997 Defender 90 300TDI. It has been converted to LED lights all round including a dashboard LED to solve the well known all indicators flashing problem. It’s just passed an MOT.

All is good until I hook up a trailer. When I plug in the trailer electrics all the LED lights on the Defender light up. The trailer has conventional lights. I couldn’t find any existing threads discussing this scenario. Any ideas?

Thanks!

Trailer without leds should be good. Check the earths on trailer & into the plug.

have you got another trailer board to check the lights?
Is it a home made trailer?

Great suggestion.

The trailer is a horse box that’s 8 years old and as it doesn’t cause a problem with a newish Discovery I just assumed the Defender to be at fault. I’ve just tried plugging in a brand new bike rack with light board into the Defender and all the lights work fine!

I will investigate the earths in the horse box.

JeepFreak said:

Great suggestion.

The trailer is a horse box that’s 8 years old and as it doesn’t cause a problem with a newish Discovery I just assumed the Defender to be at fault. I’ve just tried plugging in a brand new bike rack with light board into the Defender and all the lights work fine!

I will investigate the earths in the horse box.

Click to expand...

Bet it’s an ifor Williams??
If it is the junction box is underneath.