Thread: LED modules vs load resistors

Wouldn't the module be for earlier vehicles like a D3 where as the resistors are for trailer recognition ? I built a module for just over $50 total.

Unfortunately for what ever reason, my 2011 doesn't pick up LED based trailers & caravans. I've rewired things as I've gone along on the trailers but I've just purchased a new van so thought I'd look at an in car module so its a set & forget.

Originally Posted by rambada

Unfortunately for what ever reason, my 2011 doesn't pick up LED based trailers & caravans. I've rewired things as I've gone along on the trailers but I've just purchased a new van so thought I'd look at an in car module so its a set & forget.

You should only need resistors on the van lights.

D3s need pulse busters with resistors and relays, where D4s only need the resistors.

For a 2011 D4 you just need the appropriate resistive load on the trailer indicator circuits (one is enough but most people do both L&R for symmetry). You can achieve this by either adding resistors to every trailer you use or by just adding them inside the disco (with an on/off switch on the earth). I prefer adding them inside the disco with an on/off switch as I use several trailers. The D4 module is simply resistors mounted inside an aluminium box with thermal epoxy as a heatsink. As loanrangie said, you can make these significantly cheaper than buying them. If you ask Tombie nicely I believe he might make you one

I have a 2016 D4 and have just connected resistors (25W) to both indicators as an experiment. The dash trailer indicator now works, but the rear parking sensors have not been turned off. My understanding is that the if the D4 detects a trailer attached, it turns off the reversing sensors, adjusts the brake bias and turn on the tow assist (anti-sway). Hence I am dubious that the 2 resistors do the whole job. Thoughts people?
Do I need to put resistors on brake and tail as well?

Originally Posted by bailsie

I have a 2016 D4 and have just connected resistors (25W) to both indicators as an experiment. The dash trailer indicator now works, but the rear parking sensors have not been turned off. My understanding is that the if the D4 detects a trailer attached, it turns off the reversing sensors, adjusts the brake bias and turn on the tow assist (anti-sway). Hence I am dubious that the 2 resistors do the whole job. Thoughts people?
Do I need to put resistors on brake and tail as well?

Can you show how you’ve connected them?
And which units have you used?

Hey Tombie thanks for the quick response.
I have figured out the problem. I had forgotten about opening and closing the drivers door. Now all working fine.