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View Full Version : D3 Brake unit wiring cable sizes.



Glynhouse
11th February 2012, 08:13 AM
Sorry to do this but have read all the threads on this one that I can find.

My (new ?) D3 has a Voyager already in it, been used to tow a horse float, - looking at the plough and tongue hardly any paint off either.

The connection appears to be the same as Sniegy has posted a photo of dated 14.2.08 (http://www.aulro.com/afvb/d3-d4-rrs/51521-electric-trailer-brake-wired-photo.html) Can't see a diode there anywhere tho. has a circuit breaker back there. Was installed from new by selling dealer in Brisbane.

Wiring in the 4 wire loom that has been used is, to me, very light. with this type of set up it appears the power goes to the rear tail light then back to the brake actuator then back to the plug ??? A long route and light cables ? less than half the size that have been used in my Cruiser.

My normal method would be to pick the power feed up from the battery go to the actuator then 2 decent sized cables back to the plug, as Sniegy suggests in his current post on the D4.

Must be a reason to do it this way ? Do I try them or will the cables cook ? I tow a heavy van with 4 wheels with 12' brakes.

The blue wire that goes into the rear of the black socket is very thin but appears the plug is epoxy filled at the rear so can't do anything about changing that ! Normal ??

While I am on here I would like access to the switched power feed on the white plug, I take it that it will be epoxy filled also ? so the only way is to cut into the loom and join in further back ( behind the light ) ?

Thanks
DD

Graeme
12th February 2012, 05:39 AM
The blue wire that goes into the rear of the black socket is very thin but appears the plug is epoxy filled at the rear so can't do anything about changing that ! Normal ??
The wire is thin because it was only intended to power some tail-lights. The D4 the wire is protected by a 10A fuse so possibly the same with the D3. If I was to start towing a 4 wheel braked trailer I would replace the wire to the plug but the wire should be sufficient for 2 wheel brakes. It might even be satisfactory for 4 wheel brakes if using a proportional brake controller because the longest time the brakes are applied is probably whilst stopped at traffic lights so only low power is used. Better to replace the wire though - epoxy can be removed.

Glynhouse
12th February 2012, 09:21 PM
Thanks Graeme, I could dig it out if the cables had enough slack for me to get at them, is there a trick to it ?
Looking harder, the loom used by the dealer is actually a five wire trailer fully sheathed loom, the cables in it are 3mm Auto. or 17 gauge, the recommended in the manual is a minimum of 14 preferably 12 gauge, which is between 4 or 5mm Auto.
Thinking of using 2 of the cables linked together for the voltage feed to the brakes, then bringing a lead straight from the battery to the brake unit for the positive and earth feeds, leave the tail light sensing wire as is, but somewhere on here I thought I had seen not to connect directly to the battery with a D3 but now cant find it.

Anyone got any idea what colour wire I am looking for in the loom for the live and switched wires going to the white plug ?

Thanks

DD

Graeme
13th February 2012, 06:46 AM
When I have the bumper apart I hope to take the time to remove the trailer harness to allow access to the socket to replace the wire.

The D4 ignition switched wire to the white socket is red with white trace and the permanent supply is blue with pink trace, according to the wiring diagram.