Thread: LED trailers

D4s only need load resistors on the trailer indicator circuit to let the car know a trailer with LEDs is attached.

This will disable rear parking sensors, disable the rear fog lights, disable automatic height adjustment when a TR setting is changed (Manual height changes still work), enable a different shift program for the auto box, and flash the trailer icon on the dash when indicating.

I have wired two load resistors into the trailer socket wiring via a switch. Normal trailer lights do nothing, LED trailer lights flick switch on.

Great timing Gavin. I've been reading heaps of threads on this one. Got to the point I know I need resistors in the system on the new car (after having the full unit in the D3) but didn't want to have to do each trailer (camper, tinny, box, and lights on the bike carrier.)

@kelvo, do you have details of what you have done? Or are they in a post I've missed somewhere?

Originally Posted by kelvo

D4s only need load resistors on the trailer indicator circuit to let the car know a trailer with LEDs is attached.

This will disable rear parking sensors, disable the rear fog lights, disable automatic height adjustment when a TR setting is changed (Manual height changes still work), enable a different shift program for the auto box, and flash the trailer icon on the dash when indicating.

I have wired two load resistors into the trailer socket wiring via a switch. Normal trailer lights do nothing, LED trailer lights flick switch on.

Thanks for that, now to highjack my own thread.
I have LLAMS, and my normal driving preference is to leave LR as standard, but to drop the LLAMS devilry (almost permanently) one notch. Not only does this mean slightly lower travel, but also that I can actually fit in my garage without slamming the roofrack into the garage door.
I also propose to continue this approach when towing my 3T+ brick, particularly on gravel roads.
Any problems perceived with this approach?

Originally Posted by Dagilmo

Great timing Gavin. I've been reading heaps of threads on this one. Got to the point I know I need resistors in the system on the new car (after having the full unit in the D3) but didn't want to have to do each trailer (camper, tinny, box, and lights on the bike carrier.)

@kelvo, do you have details of what you have done? Or are they in a post I've missed somewhere?

I used these resistors 2x 25W LED 6.8Ohm Load Resistor For Hyper Turn Signal LED Controlle HOT J7C9 | eBay and this switch Round Rocker Switch - Red Actuator | Jaycar Electronics (Website description is wrong it is actually a DPDT switch).

I spliced into the left and right indicator tow socket wiring in the left hand boot compartment. These two cables connect to one pole each of the switch. I mounted the switch so it is tucked on the sloping underside near the 12v outlet on the left side in the boot. Then two cables from the switch to the resistors, the resistors are then connected to the body ground point. I mounted the resistors to an aluminium heatsink that I already had, then mounted the heatsink to the back of the towhitch bracket in the left side storage area. The photo shows the heatsink in place, but with the polystyrene hitch holder not fitted yet. The resistors are tucked away on the back so are physically protected.

Originally Posted by gavinwibrow

Thanks for that, now to highjack my own thread.
I have LLAMS, and my normal driving preference is to leave LR as standard, but to drop the LLAMS devilry (almost permanently) one notch. Not only does this mean slightly lower travel, but also that I can actually fit in my garage without slamming the roofrack into the garage door.
I also propose to continue this approach when towing my 3T+ brick, particularly on gravel roads.
Any problems perceived with this approach?

If you are permanently driving with a lower than standard ride height I would be getting a wheel alignment done at that height.

I have read widely and in reality you only need one resistor, not 2. Prior to fitting a resistor, my caravan LEDS all worked OK and the flash was consistent and not any different to a trailer attached or not. I have mine fitted to the RH circuit only. After I did that I suddenly noticed the change in driving characteristics of the car. My actual fuel usage reduced, gear changes seemed to be a touch higher in the rev range and the car seemed to have more power when driving.

Originally Posted by dirvine

I have read widely and in reality you only need one resistor, not 2. Prior to fitting a resistor, my caravan LEDS all worked OK and the flash was consistent and not any different to a trailer attached or not. I have mine fitted to the RH circuit only. After I did that I suddenly noticed the change in driving characteristics of the car. My actual fuel usage reduced, gear changes seemed to be a touch higher in the rev range and the car seemed to have more power when driving.

This is correct for the car to ‘sense’ that a trailer with LEDs is attached.

I fitted two (One on each indicator) to satisfy my OCD for dash trailer icon to flash when either indicator is used. With only one resistor fitted the dash trailer icon will only flash when indicating with the side that has the resistor fitted.

Plus when it only costs $4.45 for a pair of resistors why not fit both?

Originally Posted by kelvo

This will disable rear parking sensors, disable the rear fog lights, disable automatic height adjustment when a TR setting is changed (Manual height changes still work), enable a different shift program for the auto box, and flash the trailer icon on the dash when indicating.

Thanks Kelvo. You have given me food for thought.
Having just had my first tow experience pulling the brick, I was almost convinced I already unknowingly have the resistors fitted, cos the exercise was so effortless compared to using my D2.
However, I don't get the green towing sign, and I haven't yet checked reverse to see if the reversing sensors are turned off, rear fogs disabled etc, so a work in progress for my next tow.