My MY05 S-type has the factory trailer wiring kit which has always functioned correctly. I have a car transporter trailer that has just been overhauled and the lighting replaced by 10-30v LED units. Trailer lighting functions perfectly on another older car as do the brake (x2) and park (x6) lights when on the S-type - indicators all function correctly and flash at the correct speed (both on car and trailer). However, the clicking sound inside the car has doubled in speed and the LH / RH rear indicator bulb failure indicator comes on. I have found I can clear it by disconnecting the trailer and it only goes when I switch on the hazard flasher. I have also noticed that the reversing proximity beeper isn't silencing as it should with the trailer attached.

Are the LED units simply not using enough power to register and that triggering the warning? Any ideas as to how I can solve this would be much appreciated.
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Geoff Sparkes
Auckland, New Zealand

 

Likely not enough electrical load. I suppose extra resistors would provide enough. Really, the person who changed to LEDs should have known / warned you / fitted resistors.

 

Possibly add one or two conventional lamps to the trailer so that the car senses the electrical load.

 

Thanks for responses. Unfortunately I did the changeover as I was fed up with the vibration (no suspension on the trailer) destroying the filaments of the ordinary bulbs. Thought LEDs would solve the problem, but seems they have just created another. Looks like I have some more work to do on this.