A bit confused but I think I am right that the bulb-out system caused the trailer leds to flash and can be turned off with diagnostics. What module controls this, LCM? Car is a 2007 TDV8. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

I had to add ballast resistors to the trailer wiring - that makes them appear like bulbs to the car & the flashing works as expected.

Correct mate. Best way is too add a pair of inline resistors so it fixes that issue.

The resistors go in parallel to LED not inline (series). BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

My led trailer lights work and the car does not show any problem. My issue is The bulb out system fire a 2volt pulse out to test the bulb and it causes a flash on the led. So the question is, can I turn off the cold test via diagnostics? If so which module has the setting 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Last edited by wayneg on 31st Oct 2021 5:03am. Edited 1 time in total

I'm not sure on the Range Rover, on my Touareg with the diagnostic tool it was an option 'cold bulb test'. If it's not an option on Range Rover it wouldnt be difficult to add a resistor and capacitor combination to absorb the pulses and stop them displaying. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6