Discovery 3 LED trailer lights

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Originally Posted by swordfish805

Yes, I understand that, but things still don't seem right.

If the pulse is what is required to detect the trailer - why the need for the globe (ie for the additional resistance)?

If the globe (or other means of additional resistance) is the means of detecting the trailer - how does it work on the indicator circuit (which is where Gordon suggests installing the globe)?

It seems to me it must work under one of three scenarios:

a) there must be a pulse sent down the indicator circuit as well as the brake circuit - which means on a D3 the indicators must flash/twinkle as well as the brake lights; or

b) there is no pulse sent down the indicator circuit -instead the car waits for the indicators to be used and then senses the additional load and switches to trailer mode; or

c) the presence of a trailer is not detected by any signal on the indicator circuit and instead relies on the pulse sent down the brake circuit - in which case it seems Gordon's advice should be to install a globe on the brake circuit not the indicator circuit.

Obviously option b) is stupid - but what about a) and c)?

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Sorry - missed this earlier.

A D4 doesn't continually pulse anything - otherwise its own LEDs would flicker. However, every time the driver door is closed, it sends a single pulse down the trailer indicator circuit. If it detects a load, it configures the vehicle for an attached trailer.

At any other activation of an indicator, it also checks the load.

Cheers,

Gordon

So once detected, the trailer symbol on the dash stays on?

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Originally Posted by Epic

So once detected, the trailer symbol on the dash stays on?

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No, it only comes on with the indicator flash.

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Originally Posted by rufusking

No, it only comes on with the indicator flash.

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For both D3 and D4?
I would have presumed that the trailer symbol would stay on indicating that the anti sway features were on.

As rufusking said, on both the 3 and 4, the green trailer symbol only flashes in unison with the indicator lights. My view is that the fewer warning lights illuminated in front of me, the better I feel.

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Originally Posted by garrycol

Your logic may very well be sound - however the reality is that the D3 sends pulses down the indicator circuits -
Garry

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Finally! Thanks Garry, so it is the indicator circuit not the brake circuit (as was discussed earlier) that is pulsed? Now it makes sense.

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Originally Posted by swordfish805

Finally! Thanks Garry, so it is the indicator circuit not the brake circuit (as was discussed earlier) that is pulsed? Now it makes sense.

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Yes - I recently connected a LED trailer on my car and only the indicators pulsed - in the daylight barely noticeable and at night a little more but completely overridden when the indicators were used so not really a safety issue. All other lights worked as normal.

Garry

Fitted my new LED's to the trailer this afternoon. I've not fully soldered and shrink tubed the connections yet as I wanted to make sure all was right.
Everything works now but the tail light and number plate light. I'll have to look at it again before I tidy everything up.
Here's how I put together my load resistors.
Attachment 54472
I put a piece of 32mm aluminium between the bolts from the light and riveted the resistors on. Not my tidiest work but I had two little helpers under 4.
Thanks for the tips.

Got the tail lights to work so finished the job. And now the don't work again!

After following this thread, I rang a local caravan place who told me about this resistor that was already made up. They put me onto Repco. After my RAA membership discount, it came out to about $14.50. I bought 2, one for each side. I know some people want to attach something to their car but if you are only going to tow the one trailer, this is a cheap option. The wiring diagram is simple. You join it on either side of the light.